GitHub Web Editor does not load

The web editor (built in VSCode - https://github.dev/) from GitHub does not load anymore. Everytime you open a project it just infinitely loads but never finishes. Looking at the browsers dev tools some requests do fail, for example the workbench js file cannot be loaded with the error "NS_BINDING_ABORTED" and an subdocument fails to load (from vscode-cdn.net) with the error NS_ERROR_DOM_COEP_FAILED. I used it in the past - maybe some months or a year ago if I remember correctly - and it worked. So it is only recently broken. Adding an exception in Privacy & Security settings for github.dev does not help.