Additional features, settings, or issues not covered by specific Microsoft Teams categories
Shorter process worked for me:
- Make myself a Member in Office 365 portal.
- Save. Close.
- Create Planner.
- Remove myself as Member.
I saw on another thread that the Planner create code is getting confused that a non-Member is trying to create a Planner for the Team; it's not looking at Owners or even Global Admins.
You must be a Member of the Team to create AND USE a Planner.(Owners don't count.)