Error while fetching available custodians

This issue is seen when using the Built-in Primary Administrator account in Arctera eDiscovery. This default account is a System Administrator Only account, and does not have the required roles for Arctera eDiscovery. This account should only be used to configure Arctera Unified Platform Administration.
Use a different account with Discovery Administrator privileges assigned to it.
When trying to add custodians to a case in Arctera eDiscovery, an error is seen and no custodians are retrieved.