Mix to Stream Migration Failures

I was happily using Office Mix for its easy navigation and interactive features for my two online courses.  I have requested all my Mixes be migrated to Stream, and all of my Mixes show that they have successfully migrated under Mix, but only about a third of them actually show up on Stream.  When I click the Stream links that now show for "successfully migrated" mixes, I get the following error: "This video isn't available.  There's something wrong with the Video ID for this page."

I cannot manually re-migrate those Mixes.

I need help with this very badly-our new term starts Jan 15th!  I have two entire classes that relied on this platform!