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.
Apologies, I do not have an Adobe Muse to test this on my end. But may I know if you have already check this guide on how to embed your form there: https://www.jotform.com/help/99-Adding-a-form-to-Adobe-Muse?
I also can't view your link http://www.guhring.com.mx/, I presume it is not yet published.
If the form is disappearing, then I believe it is somehow related to the mobile responsive layout of your website, if the JotForm form is under a parent element that automatically hides depending on the screen size, then that would explain the problem. Try embedding the form outside of any element in your website.