Score upload seems to be broken

Reproducible issue affecting all scores and both of my accounts.

Uploading a score from within the Musescore program (3.3.4) using "Save Online" results in the score page displaying:
"The score cannot be uploaded, as we don't support this version of mscz files yet.
Sorry for the inconvenience."

Manually uploading an mscz file from within musescore.com results in:
"Score is being processed.
It will automatically be displayed when finished."
with the spinner animation going indefinitely. As normal, except they have been processing for over an hour now. It is stuck somewhere along the line.

Are you guys having server issues over there?

At first I thought my score was broken, and then I thought my account was broken. But as far as I can tell the issue is 100% reproducible.