Hey uhrxx005, bad news on this. I plugged your iFrame into a survey and tested the link. Autoplay was broken on mobile for me too. What is interesting though: the mobile preview autoplayed just fine. This made me question what was different on mobile vs the mobile preview in the desktop app. Here's the answer from a Stack Overflow article on the subject (top answer).
TL:DR
Autoplay on mobile is intentionally disabled on all mobile devices, both Android and iOS to save users data.

So not your iframe code that's broken but an intentional block from the mobile OS' manufacturers.