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 currently could not reproduced the issue yet on my end.
When I test submitted your jotform http://form.jotformpro.com/form/41758248099973 it was able to proceed to the Thank You page just fine after submission.
From the look on your screenshot
I can see that you have uploaded a file for the submission.
You need to wait for the upload to be completed, before the form will move on to the Thank You page.
Hope this help. Please let us know if the issue persist.