Setting Area Permissions not working

We are running Concrete 9.1.3, and I am trying to restrict the types of blocks users can add to a certain page area (not global). I selected the area, went to Permissions, selected Override Permissions. I then selected “Add Block to Area”, and all user groups are included. I then went to the “Details” tab, and disabled all of the blocks except my desired ones for all user groups.

The result: Zero blocks appearing as available when I try to add a block to that restricted area.

What could cause this?

You might check the page permissions - I believe the users still need to have the permissions to edit the page. Setting them able to edit a page area doesn’t override not being able to edit the page itself.