Hi,
I have actually tested with your live form. So please delete the 3 or 4 unpaid registrations that are named ‘test test’.
I can not find any issue with the submitted data.
Have you tried and set up sandbox account – if it works with a sandbox and not your account then the issue is with your paypal account.
You may also see that error if Encrypted Website Payments set to ON in your paypal account. Setting it to OFF will resolve the issue. This setting can be adjusted from within your PayPal account by following these steps:
(1) From your PayPal account, hover over the cog in the upper right corner of the screen and click Account Settings
(2) On the next screen, click Website Payments on the lower left
(3) On the right side of the screen, click Update next to “Website preferences”
(4) Make sure the option under “Encrypted website payments” is set to OFF
Also, is your paypal account new? If your new account isn’t fully setup or if PayPal locked it down you may see this error. Please reach out to PayPal to confirm your account is in good standing and there are no problems.