Possible issue on ib_async for connection to IBGateway, that drops immediately after successful API connection.

[edwealth888]

Title: API Connection Drops Immediately After Successful Link to IBGateway

Description:
I'm encountering a persistent issue where ib_async successfully connects to IBGateway, but the connection drops immediately afterward. This behavior occurs consistently and prevents any meaningful interaction with the API.

Environment:

• OS: Windows 11 Home
• Python Version: 3.12.10
• ib_async Version: 2.0.1
• IBGateway Version: 10.30
• VSCode Version: 1.103.0
• Connection Method: TWS API via IBGateway (issue occurs only with IBGateway; TWS works fine)

Steps to Reproduce:

1. Launch IBGateway and confirm it's running.
2. Run a basic connection script using ib_async.
3. Observe that the connection is established briefly, then drops.

Expected Behavior:
The connection should remain active and allow API calls to proceed.

Actual Behavior:
The connection is terminated immediately after being established.

Troubleshooting Attempts:

• Verified that the same behavior occurs with ib_insync.
• Tried different ports and client IDs.
• Ensured firewall and antivirus are not blocking the connection.
• Confirmed that IBGateway is properly configured and running.
• Installed ib_async via both GitHub and PyPI.
• Reproduced the issue across multiple machines.

Additional Notes:
IBKR support suggested this may be a technical issue with the ib_async library. I would appreciate any guidance or fixes the maintainers can offer.

Thank you for your help!

[gnzsnz]

check what you are doing that is producing the disconnection. I have seen a similar issue when i call ib.placeOrder with LimitOrder.lmtPrice=nan

check your logs, you should have a pointer there.

[edwealth888]

Thanks for the guidance. Here's the relevant portion of my API log:

• Connection established to IBGateway at 127.0.0.1:7497
• API handshake completed (Server version: 76, Client version: 78)
• Event loop started via util.startLoop()
• No orders placed during this session (my simple testing .py file is shown at the bottom)
• After a few normal pings, the connection closes unexpectedly:

There’s no NaN in any order parameters, and no limit orders were used. The disconnect happens even during idle sessions. Could this be related to timeout or missing heartbeat handling?

Let me know if you'd like a minimal reproducible script.
.py file:
from ib_async import *

util.startLoop()

ib = IB()
ib.connect('127.0.0.1', 4001, clientId=5)

if ib.isConnected():
print("✅ Successful connection to IB Gateway!")
else:
print("❌ Connection failed.")