Can't Save Projects, 401 Authorization Error
That's pretty much the gist. I'd say about 8 out of 10 times I try to save my project file, I get a 401 Authorization Error. The application shows that I'm logged in. Trying to save over and over again does not seem to work. I usually have to wait a day or two and hope the app doesn't crash, and even then it doesn't always work.
Comments
In order to not lose work, at least save to your computer, rather than the cloud.
I recently encountered the same issue. I saved the project to my computer (I work on Mac, so I had to go to 'Save As' in the 'File' tab on the top bar). After I made sure it was properly saved to my computer, I quit Musescore completely then reopened it with the project file. I then saved it to the cloud with no issue. Hope this helps!