Welcome to the forums @elsimater
It appears the form name is the same for the English and Spanish version. Following [Support Guide] Form problems, form debugging, 404 when submitting
The
namein the opening<form>tag needs to be unique on your site. You can reuse it on other sites.
I believe if you change the name value of the Spanish form (perhaps to contacto) both forms should get picked up by Netlify and work.