Comment 6 for bug 1936760

Yikes ok... The "classic" version is what I'd call the snap version. Passing --classic is a technical detail, which gives the snap access to the full file system.

I am concerned at how much worse it was for you... but that's not your immediate concern. It didn't help, so let's go back to square one.

First, let's remove the snap version that didn't help:
snap remove deja-dup

Then... you received a 403 error from Google. That means some sort of permission / authentication issue. Can you open the "Passwords and Keys" app and delete the "Google credentials for D�j� Dup" entry in there? That will delete any saved credentials for Google Drive that Deja Dup is keeping.

Then the next time you try to restore, it should ask you to re-grant Deja Dup access to Google Drive. Maybe that will help, to have fresh authentication tokens.