There's just a black rectangle at the top of the page when opened with Firefox for Android or Firefox Klar (Focus for German-speaking countries, telemetry disabled by default) -- even with tracking protection off.

Edit: turning uBlock Origin off helped!

For me, not even turning off ublock origin in Firefox worked. The animation was only visible in Chrome (with ublock origin activated).

I run firefox on PC and have a uBlock origin with a lot of list enabled, plus privacy badger. I can see the video with uBlock origin.

But the last piece of content to load for me.

Use uBlock origin and it will load right after the text of the article.

It wasn't loading for me. Disabling uBlock Origin didn't help either.