ORA-29377: consumer group OTHER_GROUPS is not part of top-plan

DB Version : Oracle Database 19c EE 19.9.0.0.0

I am trying to create a Resource Plan/Consumer Group which when assigned to specific users/roles will limit those users/roles to use DOP=4.

Here is what I have:

exec dbms_resource_manager.clear_pending_area();

exec dbms_resource_manager.create_pending_area();

exec dbms_resource_manager.create_plan(plan => 'MY_PLAN');

exec dbms_resource_manager.create_consumer_group(consumer_group => 'MY_GROUP');

exec dbms_resource_manager.create_plan_directive(plan => 'MY_PLAN', group_or_subplan => 'MY_GROUP', parallel_degree_limit_p1 => 4);

exec dbms_resource_manager.submit_pending_area();