Please attach a copy of your ID, passport or social security in order to receive payments *

Hi there, I'm trying to update required information in CGTrader agreement, as per the notification bar at the top of the page. However, the ID uploader doesn't seem to be working. The JPG I am trying to upload is 163 KB. I've opened/read the agreement page. I can't think of other fixes to resolve the issue. Clicking the CONFIRM AND SIGN AGREEMENT button simply returns an empty form with the notice that "Attachments can't be blank".

Thanks for advising on a solution.