In some circumstances, file permissions on Windows based installations of DellEMC NetWorker 19.1 or above can result in failures when attempting to add it as a backup server to the VA.
In order to rectify this, please ensure the user account being used for discovery has “Full Control” permission on the NetWorker nsr folder.
It may also be necessary to add read and execute permissions for the “NETWORK” built in user to nsr\bin as the discovery commands are executed over WinRM.