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 visited the link and submitted the form with blank fields, and I did end up on the "Thank You" page. It seems that it's working fine.
There are no error messages found in the display and in my console. If I may suggest, please also do check this guide we have: Which embed form code to use? We usually recommend to embed using the iFrame code.
Please do get back to us if you are still having problems or if I missed the issue you are pointing.
I hope this helps.