

I've been having this problem for a very long time as well. Ubisoft keeps asking for the logs from everyone so I had a look at the actual logs. The most informative was this part:
[Redacted]
The cache part drew my attention so I inspected the actual cache file. It consisted of a bunch of hex 0x00 character, so I deleted the file.
Afterwards I had to use my 2FA once, then the problem went away.
I haven't tested this after a reboot though, but hopefully it sticks.