iMovie project won’t play

I get a message that “some videos in this project are being downloaded from iCloud”. I made the video on my iPhone 12 and created the project on the same device. What would be downloading from iCloud? I see the thumbnail of the movie in my iMovie app on iPhone 12, but it won’t play, can’t edit, and can’t upload to YouTube. I get the same message.

I read a previous post about this that recommended unchecking the Optimize Photo option in Photos on icloud. That fix didn’t do anything for me. How do I retrieve the content in my movie project? The movie doesn’t show up on my MacBook or iPhone 6s imovie app.