CORS error on uploading assets using Firefox

Whenever I try to upload an image I see a progress indicator underneath the image, but then a popup appears with the unhelpful message “An error occurred while uploading your asset.”

Looking at the console there seems to be a CORS problem:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at<redacted>/envelope/?sentry_key=<redacted>&sentry_version=7. (Reason: CORS request did not succeed). Status code: (null).

I’m using Firefox 101.0.1 (64-bit) on Linux. Uploading does work in Chromium 103.0.5060.53.

This user seems to have had the same problem almost a year ago (it’s marked resolved, but I think they just switched browsers?):

I reached the support and apparently, Firefox is not supported passed a certain version due to some CORS rule or whatever…