OneNote in Teams is not working for everyone

Microsoft has resolved the issue.

Microsoft are having issues with OneNote in Teams at the moment. It’s possible to find the OneNote connected to the Team with the following workaround:

Go to Files in the team.
Click Open i SharePoint via the three dots in the grey area.
Click on the cogwheel in the upper right corner, and then on Site Contents
Navigate to Site Assets
You should see your OneNote here
Navigate to the menu on the left in the OneNote, it might be that the OneNote you are looking for is located under “_Collaboratin spaces”.