Permission Error as Org and Project Admin, when trying to add specific user to new project

Gulam Emadi

I am an Organization Administrator and I've just created a new project, assigning myself as the Project Administrator. When I go to the admin settings for the project and try to add access permissions for a particular user, I get a permission error: "You do not have permission to perform this action". I am, however, able to add permissions for a group. Is there a reason I am unable to add access at the individual user level?