Error occurred: Status: invalid, Detail: , Type: http-01

[Dev-l0p]

Hello ,
Thanks For this plugin .
I install this plugin in my Centos 7.3 normal server and it works perfectly .
But now when I will request for new ssl for new domain's ,Give me This Error :
Error occurred: Status: invalid, Detail: , Type: http-01

I remove AND install (reinstall) this plugin but my problem not fixed .

[hendranata]

what is the domain name?
if u want to create free ssl from sub domain.. yes it will return error
please use root domain..

i also dont know why this plugin does not work with sub domain