[Theme : Balloons] Parallax won't work anymore ?

Hi everyone,

(First I apologize for my bad English. I’m French, you know what kind of English learners we are.)
So I’ve been using the “Balloons” theme on my blog for more than a year now. Everything had been working well so far, but since this summer the balloons’ parallax effect doesn’t work anymore (example of how it should appear here : https://balloonsdemo.wordpress.com/). It happened suddenly while I didn’t edit any of the theme’s files. I even tried applying the exact same theme config to the version I developed on Wampserver, and the parallax still worked.
Is it possible that the problem might be on my host’s side (byethost22.com) ?

Thank you a lot,

Vic