Here is a screen recording showing what that web app looks like on an iPhone 14 Pro running iOS 16.2
https://www.youtube.com/results?search_query=try+galaxy
From this search I also learned this used to be called "iTest" 2 years ago.
Probably the config for HAProxy is set a little bit low or something.
But try again now. And then try again a little bit later if it continues to not load.
So when I proxy with HAProxy I was not forwarding client IP. And so Nginx and Peertube ended up thinking all connections came from same source. And this was probably leading to overly aggressive rate limiting at times.
I have now fixed parts of the configs so that now Nginx and Peertube are aware of the real client IP address.