I do not manage to upload pictures in files hosted on https://demo.hedgedoc.org/ anymore. It worked fine until this morning. I tried to copy-paste the picture, upload them with the upload button, or even the mouse dragging option, nothing works anymore. I tried to deactivate my antivirus or possible conflicting Firefox add-on (eg. ClearURL), but it did not solve the issues.
Many thanks in advance for your help !