Looks like it is somehow related to a bootup configuration file ?   (Event Viewer)

I'm not sure what file I'm looking for though.

There is no inner exception to view

Little more information found in another error in the event viewer for the MailService

After poking around, looks like the settings.json file at C:\Program Files (x86)\SmarterTools\SmarterMail\Services\Settings is corrupt, going to try and get it from backups.

Hey there Rod, you're on the right track! Your JSON configuration files were corrupted during the power outage which is an expected result unfortunately, since those files were likely being edited/read at the time. You should be able to stop the system service, restore a backup copy (we keep some in the Archived Data folder in that same directory) then start your service back up to get back online.

You may have some users in similar states though, so you can check the Error logs in Manage>Troubleshooting>View Logs for any references to password encrypted is null which will hint at that user's settings.json file being corrupted. 

I hope that helps! Let us know how it goes :)

That's great to hear Rod!