Breaking The Site (JavaScript conflict)

Hello,
It’s first time when I try to use PixelYourSite, generally it’s look very promising, great work. But…
I have some issues with javascript I think.
PixelYourSite breaking my site, please take a look at the console.

https://imgur.com/1J7IakU

https://abovethem.eu

https://abovethem.eu

Can You help me with that?

public.js?ver=7.0.5:1292 Uncaught TypeError: $(...).onFirst is not a function
    at HTMLDocument.<anonymous> (public.js?ver=7.0.5:1292)
    at i (jquery.min.js?ver=1.12.4:2)
    at Object.fireWith [as resolveWith] (jquery.min.js?ver=1.12.4:2)
    at Function.ready (jquery.min.js?ver=1.12.4:2)
    at HTMLDocument.K (jquery.min.js?ver=1.12.4:2)

The page I need help with: [log in to see the link]