I recently experienced a problem with just one PC with ‘Avast Business Security’ installed.
On logging in to the computer (domain joined) I got the message ‘The trust relationship between this workstation and the primary domain failed’. If I turn off the Web Shield using a local admin account and then login again, everything is fine.
Why would this happen? I tried updating the program version to the latest edition (17.5.2522) but it still does the same thing as I’ve just tried it again and it gives the exact same message upon trying to login.
I would consider uninstalling Avast, then remove and rejoin the PC to the domain https://support.microsoft.com/en-us/kb/2771040 and checking the computer account has indeed been deleted from AD before rejoining. Then reinstall Avast. Good luck.