I had many problems with backing up.

Kept getting notifications saying Drive Folder could not be found, invalid credentials and error connecting to server.

I disabled and reconfigured through Avast’s web portal and on app, as well as uninstalled multiple times.

What seemed to have worked for me is turning off Google’s 2-Step Verification. I think for me (and possibly others), there was some type of connection issue when having Google’s 2-Step verification enabled.

After turning that off 2-Step I:
-disabled GDrive through Avast’s web portal
-uninstalled and reinstalled app
-reconfigured everything.

Haven’t had a notice or error since.