"Invalid argument" when trying to create a folder via Zapier

I created a zap that creates a new frame.io project when I add a card in Trello. This is working fine, but I’d also like Zapier to create a folder in the new project. But it returns “invalid argument”

I also tried to choose a project instead of a dynamic ID, but it doesn’t work. It won’t show me any folders

There you see, no folders: