I had this scenario happen to me not long ago. The DBA had a script in the restore job that pu the DB in single user mode, the restore failed, and the database was stuck in single user mode. Confirm there are no errors in the job history for the restore job first.
If one brings so much courage to this world the world has to kill them or break them, so of course it kills them. The world breaks every one and afterward many are strong at the broken places. But those that will not break it kills. It kills the very good and the very gentle and the very brave impartially. If you are none of these you can be sure it will kill you too but there will be no special hurry. Earnest Hemingway, A Farewell To Arms.