Prime seems to be working now.
I just tried again and it worked. Did not remove and reinstall. Just opened the app and played my video.
So it looks like somebody fixed it, however, let's see if it continues to work.
I appreciate this forum and the fact that Danny and other listened and responded to us. I agree with the point about the blame game especially on the part of Amazon Prime. About every six months or so, there is a problem with my Roku Express + and Prime. Never happens with Netflix. And it only seems to get fixed when we contact Roku this way. If our only option was to contact Amazon Prime, it would never get fixed.
So many thanks to Danny and the team, once again.