Unable to open Musescore4 .mscz in iPad app.

I have a bit of a problem, the theatre scores I wrote are not openable in the iPad app, or I am doing something wrong. Should it work? Currently it shows just a blank page, no note lines no nothing.

If the ipad app is not compatible with Muse4 .mscz, is there a way to save the files in Muse3 format or in an iPad format?