Well, I guess that idea got blocked. So do you ever have anything save passwords? I’d like to rule out:
I can’t restore from GUI with 2.0.5.1
and there are several others. In one GitHub issue, a Firefox private browsing window solved the issue, however the better long-term solution would probably be to not let any software autofill within Duplicati.
If that isn’t it, I have no other immediate theory on why your GUI Commandline works, but GUI doesn’t.