Rob, I'm pretty much Permie's computer dinosaur, but I *do* know that people have had issues with Yo---be "shorts".
Persistence helped me the one time I tried, but I was following various instructions from this thread:
https://permies.com/t/30463/post-YouTube-video-Permies
So I'd give it a good read and try some of the suggestions. You are asking in the right spot and you're trying something which has given people a problem in the past, so please hang in there and post here again whether you manage to get it right or not. Thanks! Hopefully some of our more techie permies will post ideas.
Adding info as to what program/equipment you're using seems to help - like Chrome, windows ?, desktop - that sort of info.