Mayrink I get the same error.
Container logs are not that helpful, they show some http 500 errors when calling
/SOGoemail@example.com/Mail/0/view and if I open that page in a browser I only see a monotype phrase saying
the called object returned no result
This happens when I login from SoGo directly. If I login from the mailcow UI everything works, even SoGo. The logs show SoGo is calling dovecot fine, even when it doesn’t show anything.