I have tested your form at my site with my test Paypal account settings and it is working fine.
What I have changed in the form is that I have removed ReCaptcha since so I could test since it had keys for your site. Other than that, I have removed your business and token and entered my "Test business" and "Test token".
Therefore, here is what I think could be causing the issue.
Please try to remove ReCaptcha just to see whether the issue is somehow ReCaptcha related even though it shouldn't be.
Next, check whether the business and token that you have entered are maybe info for test account or this is a real account that you want to use?