Unable to replace Score on musescore website

Every time I export from the MuseScore app, my current score version, it loads until 40%; you can see the mixer signal coming out from each track, then stops at 42%, no signal, continues loading until 100% then gives me an error. Usually, signing out from the app and then signing in again would fix the issue, but I have been trying for two days. Also, while trying, I got a notification that there was a MuseScore update 4.5.2, so I agreed to upgrade, but still nothing different. I hate to upload manually from the website, then go and delete my original (older version). Any suggestions?