Can't access ECP - Exchange 2016

Hello,

It was a very weird issue with our ECP today.

issue: we managed to access ECP URL, but when i type my username and password, it's seems like nothing happened and there is no any error like wrong username or password, and i tried to access from local IP and External IP address same issue.

an hour after when I tried reset IIS services and check all self-signed certificates, I had access from local server in address https://127.0.0.1/ecp.

only there I success, and after couple of minutes i also manage to access from LAN and External network

Does anybody encounter with this kind of issue?

Regards,