If it is protected as a SQL Server database then remove the database from protection and recreate the protection group for ...

1) If it is protected as a SQL Server database then remove the database from protection and recreate the protection group for this database. If auto-protection is configured for the SQL Server instance of this database in DPM, then recreation of protection for this database is not required as it will be treated as a new datasource and added to protection automatically.
2) If the database is part of a SharePoint farm, this alert may get resolved automatically by DPM. Alternatively, go to the Protection pane and run "Modify Protection" for the protection group containing the SharePoint farm. In the "Modify Protection Group" wizard, expand the SharePoint front-end web server node on the "Select Group Members" page and modify the protection group. Then run consistency check on the SharePoint farm.