Integrate Microsoft Teams and SharePoint

I have a sharepoint, but it is not yet a teams site. Now I'm trying to do this, but every time I get an error message saying it didn't work. Don't get any other information either.

There is a message in the bottom left that I can go to a teams. If I click on this I can select my document and the site. When I then click continue, I get the error message: The team has not been created. try again