Can't Create a Mitigating Control

I can't create a Mitigating Control. I get the following error message: AC Owner USERNAME should come from the orgunit from Control

My Steps:

In NWBC > Setup > Mitigating Controls

I enter the General Information, Successfully

Access Risks , Successfully

In Owners, I attempt to enter a Monitor and an Approver and I get an error

i entered the Access Control Owners and went to Setup > Organizations > entered the Owner in Organizations

Do I have to do anything else?