JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
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 tried to add my form to the Facebook as an app and didn't encounter any error. Please, make sure that you are following the correct steps to do it by checking the documents from the link below:
Also, Could you please provide more information about the button? Which button is not working on your end? With those informations, we can make an healthier investigation on your issue.
I'm waiting for your answer.