Greetings to the well of knowledge...
I have an extremely vexing problem. I have several Access 2016 front-ends talking to several instances on SQL Server 2017 on a Windows 2016 VM (all fully patched). Everything was running fine until last Friday.
I suspect this is coincidence, but we are currently moving our antivirus from Symantec Endpoint Protection to Sophos Intercept X (no firewall). I removed Symantec from the VM and installed Sophos. People then started reporting that they were getting logon timeout expired errors when they launch an Access front-end. We learned that when the error occurs, the user can click OK then get a new logon window, which the user can just click OK on, and the front-end launches and the user can continue as if nothing happened. I removed Sophos on the chance that this was the cause of the problem but the problem persists. I realized that the firewall provided by Symantec Endpoint was no longer being employed and so the built-in Windows Firewall was being used. I checked the firewall and saw that our domain GPO is allowing access on ports 1433 and 1434 (and it does after getting past the timeout).
While this is usable (albeit mildly annoying), it poses a problem with one of our websites that takes form data and writes it to an instance.
Can anyone point me in a direction on how to attack this?