Adding a user to any of the local portal groups will only give the user access to specific areas of the portal. For example, adding the user to the Recovery Manager Portal – Recovery Admins group will give the user the ability to modify the portal configuration and delegate who can perform restore/undelete operations.
The actual restore operation is performed under the context of the account that was specified to Access the Domain. This setting is configured under Configuration | Active Directory Domains. Click the Domain name and the account that is used for the restore/undelete operations is the one specified under ‘Access the domain using’. If the option, ‘Recovery Manager for Active Directory instance's credentials’ is selected, the account used is the one that was specified under the setting ‘Access the computer using’ found under Configuration | Recovery Manager for Active Directory Instances | InstanceName
For a user to be able to Restore and/or Undelete, they need to be added to the appropriate local Portal group and also delegated access to where the objects reside that they will be restoring:
https://support.quest.com/recovery-manager-for-ad/kb/121880