After transferring material from a previous course to a new course (last year's course to this year's course), my students and I are getting a "invalid request" where the uploaded content should be.  This is occurring for Google Slides and Google Docs.  I am able to reattach the item from my Google Drive, but I have never had to re-add everything in the past.  Any ideas why this is happening or how to fix it?  I also have noticed that when I re-add Google Slides, I'm getting a large black band above and below the presentation.

Teresa Collier