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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.