Verify that the DPM server has DCOM launch and access permissions for %ServerName; and that the system time on the DPM server ...

1) Verify that the DPM server has DCOM launch and access permissions for %ServerName; and that the system time on the DPM server and the protected computer is synchronized with the system time on the domain controller.
2) If this computer does not need to be protected any more, you may want to remove the record for this computer from the database. To remove the record, in the Management task area, on the Agents tab, select the computer name. In the Details pane, click Remove Record.
3) Check to see that your domain controller can be reached from the DPM server and the protected computer.
4) If you are still facing communication issues between DPM and the protected computer, review the event log on the DPM server and the protected computer for events related to communication issues.
5) If %ServerName; is configured using certificates, ensure that the DPM CPWrapper service is running on DPM Server and %ServerName;. Also ensure that certificates used by both the computers are valid.