What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
I have tested your form, but I was not able to replicate mentioned issue. I successfully submitted your form and I got redirected to Thank You page.
It was probably temporary issue. Please test your form again and if the issue still persist on your end re-embed your form with iFrame code to see if that will resolve your issue. Inside of this guide you can find how to get iFrame code of your form:
Hope this will help. Let us know if you need further assistance.