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.
Did you mean you wanted the pop-up message to happen when a link or the page is loaded in your website?
From what I understand so far, it seems you want the 'Form Not Available' message to be a pop-up message. Perhaps this can be achieve already outside jotform. You can probably just add a pop-up using script in your website that will be triggered when a link or URL is click.
Share to us also the URL of your website where you used the jotform, and we will check further what we can suggest.