One of our email addresses has suddenly disappeared after several years of use. The user files are still in the homes directory for the domain, but they have gone from the user list and email to them get bounced with Recipient address rejected: User unknown in virtual alias table.
How can this happen and how do I restore the user and their emails?
How can this happen
Try Webmin->Webmin Actions Log. Personally, I would suspect someone with permission clicked the wrong thing…
how do I restore the user and their emails?
You have recent backups, yes?