The cors error seems to be more a catch-all than a real diagnostic, I actually receive the same errors if I access this on my work computer. As my current setup clearly causes some type of security issue for the backend because of the custom port and the cross-origin request to the frontend (even though it's been allowed), and it seems to be an annoyingly large percentage of the users are experiencing this my only solution will be changing to business internet. I was hoping to get away for a while without doing that, because of the increased cost with slower download speeds (and I like netflix as much as the next guy) but I'd really love it to work much better for more people. I'd also love to show it off to the cycling club at my work...
Also, I would have responded sooner but I also went out for a ride! And BBQ, it's the only thing that takes a higher priority than this for me :