SoGo SMTP Authentication Failures
We have a SoGo setup from before Cloudron supported multiple domains, and SMTP supported authenticating with just the account name.
Since the full email address is now a requirement, SoGo has been failing to send emails.
I fixed/worked around this by adding the following setting to the /app/data/sogo.conf file (instead of migrating all the data to a new SoGo instance).
SOGoForceExternalLoginWithEmail = YES;
Thought I'd share this in case anyone else runs into the same issue.