The site seems to run a little wonky for me. Not sure if you are using an app for it or through a browser but the only way the browser worked for me was either from 1. sitting on the page long enough for it to load the video and then confirm me asking to play it or 2. it only works when going full screen or some other option menu pulled up first before attempting to play it.

I will say I have used Piped in the past on desktop (which the post is asking about), and run into minimal issues but on android it may be an entirely differenbt beast. Esspecially considering people may be using browser/apps.