I can’t add songs anymore

All of a sudden, I’m not able to add songs any more.
For many years I use MuseScore on my IPad. Just to listen to files from my 2 choirs.
As usual I tried to add a new song in:
‘Available offline’ , ‘ ‘saved sheet music’, by pressing ‘+’, go to my downloads , where I added the new MuseScore ‘ file. After this it opened in MuseScore but since today ( I didn’t use it for a couple of days) not.
What’s the problem? Who can help me?