Blank pages – No source code

Hello,

I’ve got the weirdest problem going on.. My wordpress seems to work fine, the front page and blog posts are loading. But when I try to open a page (https://vrolijkvakantie.nl/contact for example) it shows a completely blank page, even without any source code showing.

What makes it more weird is that when I open the page through the admin (view page option), it works fine.

Anyone ever had this problem as well?

Disclaimer: The website got hacked at some point so the virus might have done some damage to some files.

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