Additional features, settings, or issues not covered by specific Microsoft Teams categories
In my case the connection between Teams starting up PPT was broken. Teams uses 'url' startup connection (look at Control Panel - Standard app file type overview. And I could not add this connection. I ran an Office repair (https://support.microsoft.com/nl-nl/office/office-programma-s-herstellen-7821d4b6-7c1d-4205-aa0e-a6b40c5bb88b?ui=nl-nl&rs=nl-nl&ad=nl) and it was corrected again.