Strange redirect after CF7 submit [object Object]

Hi to everyone, I’m having an error integrating this great plugin with Contact Form 7. I’m using Roots starter theme.

After submitting form, no matter if it was correctly completed or not, it redirects to a 404 page with the URL same as the one where the form was, but ending with [object%20Object].

You can find an example here: http://www.argentinadelockers.com.ar/contacto/

If you don’t fill anything and click Submit (Registrarse) this error will happen.

Did anyone have this error before?

Any help would be really appreciated.

https://wordpress.org/plugins/duracelltomi-google-tag-manager/