Can’t open my GarageBand project

Whenever I try to open my project, it gives me a pop up that reads “The song could not be opened. Please open the song after updating to the latest GarageBand.”

even though my app is up to date. My other projects seem to be just fine. I have never had this problem before and I worked pretty hard on this one so it is disappointing. Why is this happening? How can this be fixed?