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.
To my understanding, the issue that you're having occurs when your form is loaded, is that correct? Or you're experiencing that also when editing your form in the form builder page?
I have checked your form and this may be caused by the number of options in each drop-down in the Matrix fields in your form. I see that there are multiple drop-down fields in each column of your Matrix fields. That is why it's taking some time to load when you click the "Form Collapse" that holds the matrices.
It's happening on the edit
This is considered as a duplicate post. I will post my reply on this thread: https://www.jotform.com/answers/1029205.