Contact form submission

I designed a form on Webflow for my portfolio website. However, I already have an external domain and hosting service and would not like to host on Webflow as of now. So I exported my code and used PHP to try and receive the messages submitted through my form right into my email. I used the POST method and gave every input a unique name, following the right syntax and everything. However, whenever I hit submit, this is the only message I get: (click to view image)

No matter what I do, I get the above error message instantly and the form simply doesn’t go through. What can I do to change that so my form works?

Any help is appreciated… or I’d have no option but to remove the form as I’ve tried everything but it just won’t work :frowning: