Load operation failed for query get user

I have a user that is trying to load email addresses in to a 3rd party asset app that was created next to NAV by our partner.. Our partner is currently in the hospital, so i am grabbing at straws here. But we have a user that is getting the error Load operation failed for query 'GetUser'. Access to this operation was denied.
What perms do i need to give this user to complete this operation? He is trying to set an asset watch alert and when he clicks in to the screen to load the emails this is when he gets the error...
Thanks