Why is my Supply Theme Contact Us page not working?

Hello I’m having issues with my Contact Page. Its worked just fine until today. I’m using the basic page.contact that was part of the site and has worked no problem until today when I had customers contact me that it wasn’t working and I also tried it with the same issue. When you go to submit it goes to a blank page with:

This page isn’t working

If the problem continues, contact the site owner.

HTTP ERROR 400

I haven’t changed anything with the pages in a while so I don’t know why its not working all of the sudden. Here is the link to the page https://www.evolvedtuning.com/pages/contact-us

@Matt_Evolved

Did you change domains recently? If so, I believe that could be the cause of the temporary issue you experienced. It seems be working fine now:

Kind regards,
Diego

No the issue is not the Contact Page itself. When you click Submit is when you get the error page. If you fill out the form and click Send you will see whats happening.

Is anyone able to assist me with this? I have no idea how to get the Contact page working!