Administrator role missing from Roles list - how to recreate

I used AAM to create different users with different roles. I mistakenly deleted an admin and recreated it. Unfortunately, I cannot create another admin now, as Administrator does not show up in the list of Roles. Each time I launch AAM, it just shows Loading... nonstop. Please see the attached picture for my screen. I'd appreciate any help towards fixing this problem so that AAM can load correctly and I can create Administrator.