Issue publishing to Review

I'm having an issue publishing a selection of files to Review. They publish fine to LMS zips but when I try to publish to Review, the blue bar almost fills up to the end but then a message pops up saying "There was an error publishing your course to Review 360. Please check your internet connection and try again."

My internet connection is fine and I am able to publish other files to Review no problem. I have sent the files to someone else and they are getting the same error message. I've never had this issue before and it's suddenly popped up with a number of unrelated files. The only similarity I can think of is that they were all started by someone else (two different people with different files) then sent over to me for editing, but other files that were edited by others (the same people) and sent to me are publishing just fine. Some files that this is happening with are files that I could previously publish fine but I have since made a lot of changes to and now they won't publish at all. I've tried publishing under a new name and to the same location as they were in before to no avail. Some of the files have also involved copy/pasting a lot of slides from file to file, if that could cause problems, but that isn't even the case with all of the faulty files.

Does anyone have any ideas of what might be causing this or have any suggestions of what I could try to fix it?