Check the Application Event Viewer logs on the SQL Server to find out why the SQL transaction log backup may have failed. ...

Check the Application Event Viewer logs on the SQL Server to find out why the SQL transaction log backup may have failed.
You can do the following to fix the issue:
1) If the SQL log chain is broken, you will have to run a full backup to re-initialize the log chain
2) If the DPM replica for database is invalid, you will have to run a consistency check operation for this database.
Please choose an alternate point in time to recover to, if transaction log backups cannot be successfully run against database.