I purchased the ultimate plan and set up the !gpt bang to open the Kagi Assistant in the Assistant settings.
Then I changed the plan to the professional plan and created the !gpt bang in the settings. However, it didn't work.
Using the bang !gpt, I was thrown in the Kagi Docs. My assumption is, the bag tries to open the Assistant, but I am not allowed to use the Assistant, hence I got thrown into the Kagi Docs.
!gpt bang should have opened the url of the custom bag