Hive Press Filter form not working

Hey,

We are using the theme of Hive press to create our website but have recently run into an issue when using the filter form on the left hand side of the page. When using the filter form and pressing “filter” after selecting your desired attrabutes, the website goes to troubleshoot and will not load, how can this be fixed? This is very important to our website.

Cheers SoldCars

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