Problems when submitting a form

Hi:
A few days ago I installed the plugin. Everything was working fine, but today it has started to give problems. I fill out the form and press the ‘submit’ button, but an error message appears. I have cleaned the cache, and in Chrome it sends it to my pc, but not to the mobile phone. Can you help me?

Thank you very much.

The page I need help with: [log in to see the link]