When I go to:
https://trello.com/power-ups/admin/
The page doesn't recognize me being an admin of a team. I created 2 teams already and I should be an admin.
I already once was able to select a team that I am an admin of from that site and created a power-up.
The page says:
Teams
It looks like you aren't an admin of a Trello team. To administer Power-Ups, you must be an admin on a team. Once you are an admin, you will see a list of your teams here and you will be able to activate your Power-Ups for those teams.