Pardon me for being naive, I did try lastweek to configure SOGo, I might have configured it incorrectly it seems. I was able to setup several accounts, log on to them. However, I can not receive mails I sent for them. Sending did not return an error, however, logging into the recipient’s account, mail is nowhere on the mailbox.
Might be a good thing to have a how-to on SOGo installation and configuration.