V-79-57344-37951 - Database model has failed to freeze for the snapshot backup.

In typical Backup Exec form, everything was working fine until this error starting popping on one of my backup jobs. The backup job is backing up a domain controller where the Backup Exec server itself resides. 

BE21.2:

Completed status: FailedFinal error: 0xe000943f - Database s failed to freeze for backup.  This can be caused if the database is in a state that does not support backup; such as offline, standby, or recovering.   Final error category: Other Errors

The database in question is the actual Backup Exec SQL database. All articles on the net and in the community are mostly pointing to a credentials issue, but the credentials for the database test successfully. Again, this was working previously. Further digging on the net pointed towards the SQL VSS Writer or service being missing--lo and behold--they are both missing. 

1. How do I get the service and writer back? I ran a repair on BE21.2 hoping it would fix the issue, but it didn;'t since this is a SQL issue.

2. Should I run a repair on the database using the BEUtility?

3. I unchecked the BE SQL database from the backup to see if it fixes the problem, but that seems like a workaround rather than a real solution. 

4. Should I just upgrade to BE22? A new upgraded database will be installed if I'm correct (SQL2017). Will this fix the problem?

Any ideas?