Hello! Today some of our participants encountered an upload problem with seemingly normal JPEG photos. They all see the rather incomprehensible error message "An error was encountered when opening the file for ZIP checks", and the upload fails. I created a Phabricator ticket https://phabricator.wikimedia.org/T223446 but would also like to ask around if anyone has had this problem before. I am quite sure that last year it was not there. best, Alexander