Android - cannot connect to SQL Server Express 2019 using any casual SqlClient version (v2.1.4, v4.1.0, v5Preview)

[janseris]

Describe the bug

Edit: please use the test application version added in the latest comment in this issue (more functions, less hardcoded)

Introduction:

• there is no issue on Windows
• on Windows, you should be seeing this with the sample app:
  • 
  • run as

This is a continuation of this issue:
#1656
There, only Android 9 and higher can communicate with a SQL Server 2012 with latest patch and a valid certificate from DigiCert.
The message in SqlException is always the same for both of these issues:
(A connection was successfully established with the server, but then an error occurred during the pre-login handshake.)

---

In this issue, I have set up a local SQL Server Express 2019 instance and opened it to the local network (port 1433).
TCP/IP connection is enabled and a SQL account for authentication is set.

These versions of SQL Server API from C# fail to communicate to the instance from Android (.NET MAUI):

• Microsoft.Data.SqlClient 2.1.4 (EF Core 6.0.6)
• Microsoft.Data.SqlClient 5.0.0-preview2.22096.2 (EF Core 7.0.0-preview.5.22302.2)
• Microsoft.Data.SqlClient 4.1.0
• Microsoft.Data.SqlClient 2.0.0
• Microsoft.Data.SqlClient 5.0.0-preview3.22168.1
• System.Data.SqlClient 4.8.3

Result of the test:
No Android verison can communicate with the SQL Server Express 2019 instance properly after connection

• all SqlClient versions have the same result on all Android versions when trying to communicate with the SQL Server 2019 instance -> "...pre-login handshake failed..." SqlException of Class 20 (A connection was successfully established with the server, but then an error occurred during the pre-login handshake.)
  The Android devices do in fact connect to the server, because if they did not, I would have received a different SqlException.
• using TrustServerCertificate=true; and/or Encrypt=false; does not help solving the error

Test project:

• janseris/MAUI_SQLServer_Test@8ee2e00

About the test project:

• note: watch the Debug Output window or place a breakpoint or execute step-by-step with debugger to observe the results (Label UI controls (which are supposed to show the text result) in MAUI are bugged and do not show on Android)
• it executes a DB call using the list of SqlClients listed above

---

Here a detailed look into a separate test of Microsoft.Data.SqlClient 2.1.4 (EF Core 6.0.6 = current) alone:

The following are results (debug output from Visual Studio) with internal errors on Android versions 5,6,8,9,11,12 for attempted communication with SQL Server Express 2019 (all fail with the same error "pre-login handshake...") for EF COre 6.0.6 (using SqlClient 2.1.4 internally)

• Android 5 emulator:
  • no internal exception shown
• Android 6 emulator:
  • no internal exception shown
• Android 8 emulator:
  • this happens for SQL Server 2012 as well

  •   [System.err] 	at com.android.org.conscrypt.OpenSSLEngineImpl.beginHandshakeInternal(OpenSSLEngineImpl.java:335)
      [System.err] 	at com.android.org.conscrypt.OpenSSLEngineImpl.beginHandshake(OpenSSLEngineImpl.java:325)
      [System.err] 	at crc64fcf28c0e24b4cc31.ButtonHandler_ButtonClickListener.n_onClick(Native Method)
      [System.err] 	at crc64fcf28c0e24b4cc31.ButtonHandler_ButtonClickListener.onClick(ButtonHandler_ButtonClickListener.java:30)
      [System.err] 	at android.view.View.performClick(View.java:6256)
      [System.err] 	at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1194)
      [System.err] 	at android.view.View$PerformClick.run(View.java:24701)
      [System.err] 	at android.os.Handler.handleCallback(Handler.java:789)
      [System.err] 	at android.os.Handler.dispatchMessage(Handler.java:98)
      [System.err] 	at android.os.Looper.loop(Looper.java:164)
      [System.err] 	at android.app.ActivityThread.main(ActivityThread.java:6541)
      [System.err] 	at java.lang.reflect.Method.invoke(Native Method)
      [System.err] 	at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
      [System.err] 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)```
    
    

• Android 9 emulator:
  • no internal exception shown
• Android 11 emulator:
  • this does not happen for SQL Server 2012
  • this happens with Encrypt=false and TrustServerCertificate=true

  • [System.err] 	at com.android.org.conscrypt.SSLUtils.toSSLHandshakeException(SSLUtils.java:362)
    [System.err] 	at com.android.org.conscrypt.ConscryptEngine.convertException(ConscryptEngine.java:1134)
    [System.err] 	at com.android.org.conscrypt.ConscryptEngine.readPlaintextData(ConscryptEngine.java:1089)
    [System.err] 	at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:876)
    [System.err] 	at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:747)
    [System.err] 	at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:712)
    [System.err] 	at com.android.org.conscrypt.Java8EngineWrapper.unwrap(Java8EngineWrapper.java:237)
    [System.err] 	at crc64fcf28c0e24b4cc31.ButtonHandler_ButtonClickListener.n_onClick(Native Method)
    [System.err] 	at crc64fcf28c0e24b4cc31.ButtonHandler_ButtonClickListener.onClick(ButtonHandler_ButtonClickListener.java:30)
    [System.err] 	at android.view.View.performClick(View.java:7448)
    [System.err] 	at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1194)
    [System.err] 	at android.view.View.performClickInternal(View.java:7425)
    [System.err] 	at android.view.View.access$3600(View.java:810)
    [System.err] 	at android.view.View$PerformClick.run(View.java:28305)
    [System.err] 	at android.os.Handler.handleCallback(Handler.java:938)
    [System.err] 	at android.os.Handler.dispatchMessage(Handler.java:99)
    [System.err] 	at android.os.Looper.loop(Looper.java:223)
    [System.err] 	at android.app.ActivityThread.main(ActivityThread.java:7656)
    [System.err] 	at java.lang.reflect.Method.invoke(Native Method)
    [System.err] 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
    [System.err] 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
    [System.err] Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
    [System.err] 	at com.android.org.conscrypt.TrustManagerImpl.verifyChain(TrustManagerImpl.java:677)
    [System.err] 	at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:554)
    [System.err] 	at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:510)
    [System.err] 	at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:428)
    [System.err] 	at com.android.org.conscrypt.TrustManagerImpl.getTrustedChainForServer(TrustManagerImpl.java:371)
    [System.err] 	at android.security.net.config.NetworkSecurityTrustManager.checkServerTrusted(NetworkSecurityTrustManager.java:102)
    [System.err] 	at android.security.net.config.RootTrustManager.checkServerTrusted(RootTrustManager.java:106)
    [System.err] 	at com.android.org.conscrypt.Platform.checkServerTrusted(Platform.java:250)
    [System.err] 	at com.android.org.conscrypt.ConscryptEngine.verifyCertificateChain(ConscryptEngine.java:1644)
    [System.err] 	at com.android.org.conscrypt.NativeCrypto.ENGINE_SSL_read_direct(Native Method)
    [System.err] 	at com.android.org.conscrypt.NativeSsl.readDirectByteBuffer(NativeSsl.java:568)
    [System.err] 	at com.android.org.conscrypt.ConscryptEngine.readPlaintextDataDirect(ConscryptEngine.java:1095)
    [System.err] 	at com.android.org.conscrypt.ConscryptEngine.readPlaintextDataHeap(ConscryptEngine.java:1115)
    [System.err] 	at com.android.org.conscrypt.ConscryptEngine.readPlaintextData(ConscryptEngine.java:1087)
    [System.err] 	... 18 more
    [System.err] Caused by: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
    [System.err] 	... 32 more```
    
    

• Android 12 emulator:

  •     [System.err] 	at com.android.org.conscrypt.SSLUtils.toSSLHandshakeException(SSLUtils.java:363)
        [System.err] 	at com.android.org.conscrypt.ConscryptEngine.convertException(ConscryptEngine.java:1134)
        [System.err] 	at com.android.org.conscrypt.ConscryptEngine.readPlaintextData(ConscryptEngine.java:1089)
        [System.err] 	at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:876)
        [System.err] 	at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:747)
        [System.err] 	at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:712)
        [System.err] 	at com.android.org.conscrypt.Java8EngineWrapper.unwrap(Java8EngineWrapper.java:237)
        [System.err] 	at crc64fcf28c0e24b4cc31.ButtonHandler_ButtonClickListener.n_onClick(Native Method)
        [System.err] 	at crc64fcf28c0e24b4cc31.ButtonHandler_ButtonClickListener.onClick(ButtonHandler_ButtonClickListener.java:30)
        [System.err] 	at android.view.View.performClick(View.java:7441)
        [System.err] 	at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1194)
        [System.err] 	at android.view.View.performClickInternal(View.java:7418)
        [System.err] 	at android.view.View.access$3700(View.java:835)
        [System.err] 	at android.view.View$PerformClick.run(View.java:28676)
        [System.err] 	at android.os.Handler.handleCallback(Handler.java:938)
        [System.err] 	at android.os.Handler.dispatchMessage(Handler.java:99)
        [System.err] 	at android.os.Looper.loopOnce(Looper.java:201)
        [System.err] 	at android.os.Looper.loop(Looper.java:288)
        [System.err] 	at android.app.ActivityThread.main(ActivityThread.java:7839)
        [System.err] 	at java.lang.reflect.Method.invoke(Native Method)
        [System.err] 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
        [System.err] 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
        [System.err] Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
        [System.err] 	at com.android.org.conscrypt.TrustManagerImpl.verifyChain(TrustManagerImpl.java:672)
        [System.err] 	at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:549)
        [System.err] 	at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:505)
        [System.err] 	at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:425)
        [System.err] 	at com.android.org.conscrypt.TrustManagerImpl.getTrustedChainForServer(TrustManagerImpl.java:368)
        [System.err] 	at android.security.net.config.NetworkSecurityTrustManager.checkServerTrusted(NetworkSecurityTrustManager.java:102)
        [System.err] 	at android.security.net.config.RootTrustManager.checkServerTrusted(RootTrustManager.java:106)
        [System.err] 	at com.android.org.conscrypt.Platform.checkServerTrusted(Platform.java:255)
        [System.err] 	at com.android.org.conscrypt.ConscryptEngine.verifyCertificateChain(ConscryptEngine.java:1638)
        [System.err] 	at com.android.org.conscrypt.NativeCrypto.ENGINE_SSL_read_direct(Native Method)
        [System.err] 	at com.android.org.conscrypt.NativeSsl.readDirectByteBuffer(NativeSsl.java:569)
        [System.err] 	at com.android.org.conscrypt.ConscryptEngine.readPlaintextDataDirect(ConscryptEngine.java:1095)
        [System.err] 	at com.android.org.conscrypt.ConscryptEngine.readPlaintextDataHeap(ConscryptEngine.java:1115)
        [System.err] 	at com.android.org.conscrypt.ConscryptEngine.readPlaintextData(ConscryptEngine.java:1087)
        [System.err] 	... 19 more
        [System.err] Caused by: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
        [System.err] 	... 33 more```
    
    

• Android 12 device
  - [System.err] javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found. [System.err] at com.android.org.conscrypt.SSLUtils.toSSLHandshakeException(SSLUtils.java:363) [System.err] at com.android.org.conscrypt.ConscryptEngine.convertException(ConscryptEngine.java:1134) [System.err] at com.android.org.conscrypt.ConscryptEngine.readPlaintextData(ConscryptEngine.java:1089) [System.err] at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:876) [System.err] at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:747) [System.err] at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:712) [System.err] at com.android.org.conscrypt.Java8EngineWrapper.unwrap(Java8EngineWrapper.java:237) [System.err] at crc64fcf28c0e24b4cc31.ButtonHandler_ButtonClickListener.n_onClick(Native Method) [System.err] at crc64fcf28c0e24b4cc31.ButtonHandler_ButtonClickListener.onClick(ButtonHandler_ButtonClickListener.java:30) [System.err] at android.view.View.performClick(View.java:7451) [System.err] at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1194) [System.err] at android.view.View.performClickInternal(View.java:7425) [System.err] at android.view.View.access$3700(View.java:842) [System.err] at android.view.View$PerformClick.run(View.java:28690) [System.err] at android.os.Handler.handleCallback(Handler.java:938) [System.err] at android.os.Handler.dispatchMessage(Handler.java:99) [System.err] at android.os.Looper.loopOnce(Looper.java:346) [System.err] at android.os.Looper.loop(Looper.java:475) [System.err] at android.app.ActivityThread.main(ActivityThread.java:7889) [System.err] at java.lang.reflect.Method.invoke(Native Method) [System.err] at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548) [System.err] at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1009) [System.err] Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found. [System.err] at com.android.org.conscrypt.TrustManagerImpl.verifyChain(TrustManagerImpl.java:672) [System.err] at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:549) [System.err] at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:505) [System.err] at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:425) [System.err] at com.android.org.conscrypt.TrustManagerImpl.getTrustedChainForServer(TrustManagerImpl.java:368) [System.err] at android.security.net.config.NetworkSecurityTrustManager.checkServerTrusted(NetworkSecurityTrustManager.java:102) [System.err] at android.security.net.config.RootTrustManager.checkServerTrusted(RootTrustManager.java:106) [System.err] at com.android.org.conscrypt.Platform.checkServerTrusted(Platform.java:255) [System.err] at com.android.org.conscrypt.ConscryptEngine.verifyCertificateChain(ConscryptEngine.java:1638) [System.err] at com.android.org.conscrypt.NativeCrypto.ENGINE_SSL_read_direct(Native Method) [System.err] at com.android.org.conscrypt.NativeSsl.readDirectByteBuffer(NativeSsl.java:569) [System.err] at com.android.org.conscrypt.ConscryptEngine.readPlaintextDataDirect(ConscryptEngine.java:1095) [System.err] at com.android.org.conscrypt.ConscryptEngine.readPlaintextDataHeap(ConscryptEngine.java:1115) [System.err] at com.android.org.conscrypt.ConscryptEngine.readPlaintextData(ConscryptEngine.java:1087) [System.err] ... 19 more [System.err] Caused by: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found. [System.err] ... 33 more

To reproduce

• have a working SQL Server Express 2019 instance exposed to the network (this tutorial will do: https://www.youtube.com/watch?v=xNmIdFjXzl4)
  • set up a SQL Server Express 2019
  • open port 1433 on firewall
  • configure the SQL Server Express instance to allow SQL authentication
  • enable an account on the instance (e.g. sa)
  • configure the instance to allow TCP/IP connection on port 1433
• be able to run the MAUI application
  • download latest VS 2022 Preview (because MAUI can only be used in VS 2022 Preview)
  • add the MAUI part in Visual Studio Installer
    • 
  • install some Android emulators (default settings are OK) via Visual Studio ->
    
    • or use physical device - after connecting via USB and enabling USB debugging, you should be able to see and use it as follows:
      • 

Note:

• the connection strings which are hardcoded into the sample app, have the following properties:
  • Database Ordinace devRemin
  • SQL account name sa
  • SQL account password sa
  • a table called USER in the default dbo schema
    • the EF test projects require that it has some columns but you can skip using the EF Core projects because they use SqlClient anyways
      • the other projects simply select number of rows from the USER table (could have selected something from a dummy table or be doing SELECT 'Hello World') the current version simply executes SELECT LEN('Hello World')

Note dotnet/maui#2:

• the Constants.LocalNetworkConnectionString string has a hardcoded private IP of 192.168.0.234
  • this IP will probably be different in every local network
  • the correct IP can be obtained via running the command line command ipconfig on the host machine running the SQL Express (this example requires that the Android device and the machine hosting the SQL Server are in the same local network so that private IP can be used (or you can share your SQL Server Express to the internet and use a public IP address in fact but I did not do that)
    • look for IPv4 Address entry in the output of the ipconfig command, that's the private/local IP address

Expected behavior

Android can communicate with the SQL Server Express.

Further technical details

.NET target: .NET 6.0 (dotnet --version: 6.0.400-preview.22301.10)
SQL Server version: SQL Server Express 2019
Operating system: Windows 10 21H1

[janseris]

Note: EF Core 6.x.x uses Microsoft.Data.SqlClient which uses Encrypt=false by default (Encrypt=true is by default used on Microsoft.Data.SqlClient 4.0.0+)

Day 2:

• tried older EF Core 6.0.1 Blazor Server application
  • works on the same computer on the same SQL Server Express instance without TrustServerCertificate=true and without Encrypt=false (the connection string is simply Server=LAPTOP-HGEN5Q27\\SQLEXPRESS;Database=Ordinace;Integrated Security=True;
  • this works without any error about certificate validation
• the same connection string executed from MAUI Windows application requires TrustServerCertificate=true or Encrypt=false else it keeps saying SqlException Class: 20, Number: -2146893019, Message: A connection was successfully established with the server, but then an error occurred during the login process. (provider: SSL Provider, error: 0 - The certificate chain was issued by an authority that is not trusted.)
• the same connection string used from SMSS outputs the error as well (simulating Microsoft.Data.SqlClient behavior using Encrypt=true):
  • 

I read here: https://docs.microsoft.com/en-us/sql/connect/ado-net/introduction-microsoft-data-sqlclient-namespace?view=sql-server-ver15#breaking-changes-in-40 That since verison 4.0.0, Microsoft.Data.SqlClient uses Encrypt=true request on server (which if it can, then encrypts the data transfer communication).

What is strange about this is inconsistency: EF Core 6.0.1 on one project does not output the error and on the other one it does (and incorrectly because Microsoft.Data.SqlClient 2.1.4 should be not encrypting by default.

Why doesn't it work in a way such that this error about certificate on Windows is received only on parts with Microsoft.Data.SqlClient 4.0.0 and newer? Why is this error received with Microsoft.Data.SqlClient 2.1.4 and also with System.Data.SqlClient 4.8,3?

[janseris]

The app has been updated for faster testing and examination.
The latest version is here: janseris/MAUI_SQLServer_Test@72b40bf janseris/MAUI_SQLServer_Test@52b2a18

It now allows selecting connection string, entering a custom connection string, adding suffixes to the connection string, disable connection pooling (that did not help getting different results on different versions of SqlClient on Windows machine concerning the certificate though) etc.

The results for me are (for all versions of SqlClient):

• SQL Server Express 2019 local instance: no Android device can communicate and Windows devices can communicate only when ignoring the certificate
• SQL Server 2012 latest patch: Android 9+ devices can communicate and all Windows devices can communicate

What is the expected result:

• the SQL Server Express 2019 should be fully accessible by any Android version and on Windows the certificate should not be checked when older SqlClient than 4.0.0 is used (because then Encryption is not enabled)
• the SQL Server 2012 should be fully accessible by any Android version

P.S. results are printed to Debug Output as well.

[JRahnama]

Hi @janseris is this a duplication of #1656?

[janseris]

Hi @janseris is this a duplication of #1656?

Hi, no it is not but the sample app can be used to test both.
This is mostly about that no Android can connect to SQL Express 2019 with errors varying between Android versions, the newest versions outputting Trust anchor for certification path not found. even when the certificate is explicitly ignored in connection string as mentioned earlier.

And also about inconsistent certificate issues (randomly yes and no) with SQL Express 2019 when connecting from Windows but there is a workaround for that by ignoring the certificate so it is not important.

There is no workaround for the Android issue though and it's fatal.

I believe there is an issue with various other versions of SQL Server or SQL Server Express called from Android because I saw multiple threads about that and none with a solution but I don't have access to more versions than these which I documented so I cannot tell for other SQL Server versions.

[JRahnama]

one other step to check before going deeper into the issue. Can you look into Sql Server Configuration Manager , expand Sql Server Network Configuration right click on Protocols for <your instance name> and select property. You will see a window similar to below:

and make sure the Force Encryption is set to No. Also when you look into Protocols for <your instance name>, on the right hand side column, can you let me know what protocol names are enabled?

[stegl83]

Hi @janseris,

we spend a LOT of hours to get this working.

You have to use certificates, without them there is no connection possible.
This is our way to achieve the successful connection:

Setup the Device and Server

1. create a selfsigned Cert, consider this:
   • the Flag "CA:TRUE" must be set
   • set the commonName to the ServerName like this: [PCName].[Domain].local
   • Build a CRT-File and a PFX
2. install the CRT-File on the device and the PFX on the Server
   (we have installed the cert in the Store "Computer/own Cert" and make a copy to "trustworthy root... " (in german it was "Vertrauenswürdige Stammzertifizierungsstellen")
3. Set Permission -> "Manage Private Keys" see Link below (2)
4. you can now select the cert in the certicate-Tab in SQL Configuration Mgr
   (SQL-Network config -> Right click on Protocols)
5. restart SqlService

Setup the MAUI-App (You have to explicitly allow User Certificates)

1. AndroidManifest (in application-tag): android:networkSecurityConfig="@xml/network_security_config"

2. include "network_security_config.xml" in project
   network_security_config.zip

3. ConnectionString like this:
   Data Source=[PCName].[Domain].local; ... ;Trust Server Certificate=True

Give a Try.

Links:
(1) https://codekabinett.com/rdumps.php?Lang=2&targetDoc=create-install-ssl-tls-certificate-sql-server
(2) https://stackoverflow.com/questions/36830411/how-can-i-give-sql-server-permission-to-read-my-ssl-key

[DavoudEshtehari]

@janseris were you able to make a connection to server with the provided information above?

[janseris]

@janseris were you able to make a connection to server with the provided information above?

Hi, I had days off last week. I hope to get to this later this week. I haven't tried yet but saw your tips. Thank you.

[FikretAkin]

Hello, I've been dealing with this error for 2-3 days, SQL SERVER 2019 Express is installed and all settings are done, even if I install the certificate, it is not accepted, I am trying to connect with DbCOntext via EF CORE.
Error detail;

[System.err] javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found. [System.err] at com.android.org.conscrypt.SSLUtils.toSSLHandshakeException(SSLUtils.java:363) [System.err] at com.android.org.conscrypt.ConscryptEngine.convertException(ConscryptEngine.java:1134) [System.err] at com.android.org.conscrypt.ConscryptEngine.readPlaintextData(ConscryptEngine.java:1089) [System.err] at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:876) [System.err] at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:747) [System.err] at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:712) [System.err] at com.android.org.conscrypt.Java8EngineWrapper.unwrap(Java8EngineWrapper.java:237) [System.err] at crc64fcf28c0e24b4cc31.ButtonHandler_ButtonClickListener.n_onClick(Native Method) [System.err] at crc64fcf28c0e24b4cc31.ButtonHandler_ButtonClickListener.onClick(ButtonHandler_ButtonClickListener.java:30) [System.err] at android.view.View.performClick(View.java:7509) [System.err] at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1194) [System.err] at android.view.View.performClickInternal(View.java:7486) [System.err] at android.view.View.-$$Nest$mperformClickInternal(Unknown Source:0) [System.err] at android.view.View$PerformClick.run(View.java:29358) [System.err] at android.os.Handler.handleCallback(Handler.java:942) [System.err] at android.os.Handler.dispatchMessage(Handler.java:99) [System.err] at android.os.Looper.loopOnce(Looper.java:201) [System.err] at android.os.Looper.loop(Looper.java:288) [System.err] at android.app.ActivityThread.main(ActivityThread.java:7892) [System.err] at java.lang.reflect.Method.invoke(Native Method) [System.err] at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548) [System.err] at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936) [System.err] Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found. [System.err] at com.android.org.conscrypt.TrustManagerImpl.verifyChain(TrustManagerImpl.java:670) [System.err] at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:547) [System.err] at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:503) [System.err] at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:423) [System.err] at com.android.org.conscrypt.TrustManagerImpl.getTrustedChainForServer(TrustManagerImpl.java:366) [System.err] at android.security.net.config.NetworkSecurityTrustManager.checkServerTrusted(NetworkSecurityTrustManager.java:102) [System.err] at android.security.net.config.RootTrustManager.checkServerTrusted(RootTrustManager.java:106) [System.err] at com.android.org.conscrypt.Platform.checkServerTrusted(Platform.java:255) [System.err] at com.android.org.conscrypt.ConscryptEngine.verifyCertificateChain(ConscryptEngine.java:1638) [System.err] at com.android.org.conscrypt.NativeCrypto.ENGINE_SSL_read_direct(Native Method) [System.err] at com.android.org.conscrypt.NativeSsl.readDirectByteBuffer(NativeSsl.java:569) [System.err] at com.android.org.conscrypt.ConscryptEngine.readPlaintextDataDirect(ConscryptEngine.java:1095) [System.err] at com.android.org.conscrypt.ConscryptEngine.readPlaintextDataHeap(ConscryptEngine.java:1115) [System.err] at com.android.org.conscrypt.ConscryptEngine.readPlaintextData(ConscryptEngine.java:1087) [System.err] ... 19 more [System.err] Caused by: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found. [System.err] ... 33 more **Microsoft.Data.SqlClient.SqlException:** 'A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 35 - An internal exception was caught)'

[janseris]

@DavoudEshtehari, @stegl83
Hi, @FikretAkin tried the certificate and didn't work.
I am too busy, sorry.