Planner tab error in new teams created using the admin center
When a Teams service administrator creates a new team from the Microsoft Teams admin center and adds himself as the owner of the team, it would not be able to create a Planner tab on that team.
When trying to create a new Planner tab in any of the the team channels, an error saying 'Failed to create the plan' would appear (see the attached file).
Not only that, if any another team owner creates the planner tab for him, he will not be able to access it, and the error changes to 'Something went wrong' -indeed-.
In order to be able to access the planner tab, another Teams service administrator needs to remove that owner from that team and add it again.
Rory de Leur commented
Same problem is described on the tech forums (https://answers.microsoft.com/en-us/msoffice/forum/all/create-plan-failed-when-creating-planner-in/385660aa-ba9e-4ed8-9d55-896d752589a4) on november 9th of last year but the problem still exists.