Internal server error on my form using sandbox PayPal

I get  this error:

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, webmaster@paypal.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

When I try to test my jotform from my website and if I run the from from the direct link given in jotforms I get to the paypal screen but it will not accept my password. 

Form is at

I have tried submitting your form and see that the form is redirected to PayPal without any issue. I have tried logging into my PayPal Sandbox account and able to make the payment on your form. 

You may try signing up for a different PayPal sandbox account and make the payment to see if that works. Please check and let us know if you need any further assistance.

Thanks!