Avamar: Unable to add or edit a Data Domain due to incorrect ddr_key file permissions

Attempting to add a Data Domain results in the following error:

Unable to add SNMP Community string to Data Domain System 
Code: 31011

Attempting to edit a Data domain, error code 30973 appears with the following:

The file system is disabled on the Data Domain system. The file system must be enabled in order to perform backups and restores

The following error is seen in /usr/local/avamar/var/mc/server_log/mcserver.log.0:

WARNING: java.io.FileNotFoundException: /usr/local/avamar/lib/ddr_key (Permission denied)

The Data Domain file system is running.

There is a permission or ownership issue on the ddr_key on the Avamar Utility Node.

1. Log in to the Avamar Utility Node as admin.

2. Elevate to root privilege.

3. Verify the current ownership and permission:

ls -al /usr/local/avamar/lib/ddr_key

Example output:

-r--r---- 1 root admin 1.7K Apr 11 11:01 /usr/local/avamar/lib/ddr_key

If the permissions are anything other than the above ( -r--r----- ), run the following command:

chmod 440 /usr/local/avamar/lib/ddr_key 

If the ownership is anything other than the above (root admin), run the following command:

chown root:admin /usr/local/avamar/lib/ddr_key 

If any changes are made, verify that the ownership and permissions are now correct by performing step 3 again.

If the issue is not resolved, Create a Service Request with the Dell Technologies Avamar Support team.