Can't upload document on etudiant-etranger.ameli.fr

Hi. While all other documents have been accepted, my residency permit was rejected as an "invalid document." However, I can't seem to upload the correct document. After providing the details of the document and clicking save, nothing happens. I've been trying to use different files, file types and browsers to no avail. They are all in the accepted file sizes and formats. How to fix this?