Add User Group by CSV - Failed (User not found in organization)

Hello,

I have been trying to bulk create user groups (based on department id) and I am getting a failed result due to the assigned administrator "Not found in Organization".

The administrator that was assigned is listed as the Contract Holder and System Administrator in the Administrators tab... and is appearing in the full users list (it is me).

I am not sure why I keep getting this error. Any advice is appreciated.