NetWorker: All backups sent to Data Domain are failing with "no matching devices for save of client"

• All backups sent to Data Domain start failing with "no matching devices."
• The NetWorker Management Console (NMC) reports:

no matching devices for save of client '[client_name]'; check storage nodes, devices or pools

• The NetWorker Server daemon.raw reports the following error:

SYSTEM critical Failed to connect to [Data_Domain]

• • NetWorker: How to use nsr_render_log to render .raw log files
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• When testing the connection to the DD, all connection test (ping, nslookup, and so forth) comes back fine.

Update the ddboost user password.

1. In a web browser, go to the Data Domain user interface: https://DD_ADDRESS
2. Log in with the sysadmin account.
2. Click Administration -> Access, then click Local Users.
3. Select the ddboost user account used by the NetWorker devices.
4. Click Change Password

5. Ensure the ddboost user account shows Enabled, if locked or disabled, click Enable.
6. Log in to the NetWorker Management Console.
7. Go to Devices->Devices.
8. For each device configured against the affected Data Domain, update the ddboost user password.

9. Ensure that the device can be mounted. 
10. Rerun the failed job.

This error has other potential causes. If the ddboost account is not locked, see: NetWorker: Troubleshooting Media Waiting Events - waiting for one writable volume or no matching devices