Hey @Nina5FCD, Thanks for reaching out, and welcome to our Adobe Express community!
Did you add any new assets to the project or use any new font that was not there when you previously downloaded the app? If yes, can you try replacing it with any different asset or font, to see if that helps.
You may also want to look out for any layers that show up empty in the layers stack on the right side of the screen. If you find any such empty layer, delete it and try downloading the project again.