Betheme icons and some of the visual composer (muffin builder) items dont show

Hi guys

I have some errors on my website that I'm trying to solve (so far no luck)

1st problem: all icons disappeared from the website (yes I checked the fonts, they are stored in the fonts folder)
im getting errors in my browser console (see attachments)


console:


2nd problem: some of the muffin builder elements dont show up (during refresh I can see them, but they disappear quickly after the website is reloaded)
console (i think this has something to do with it):

these list items are completely gone

Only one box appears lol


Please help me out, i tried almost everything that i could think of

Thanks