I checked the SystemSettings file and it was blank. I had a backup and restored it and now the site works again. I'm 100% positive no one edited this file but it does say it was edited recently. How could this happen? Is it supernatural?

Good morning! This scenario leads me to believe something may have corrupted or locked the settings/configuration files. In our latest releases this is frequently the settings.json file found in our system root. Did you have any unexpected restarts of the server, or do you operate any third party antivirus that might be locking our files?

We had an incident after an unexpected restart. A user tried to login to webmail, but instead of the login page, he was offered Setup Wizard. And followed through with it, which in the end resulted with mail server's configuration reset to defaults. This was a server with thousands of mailboxes.
This should be maybe addressed in some way, other than us manually disabling access to file setup-wizard.html.

Kind regards