mactonio on "Polylang & Vantage theme - "Are you sure?" Error after creating menus"

I'm having the same problem.
According to wordpress support website is a problem with the polylang plugin that has problems with nonce verification fails.

here you are the link of the article.

http://www.wpbeginner.com/wp-tutorials/how-to-fix-are-you-sure-you-want-to-do-this-error-in-wordpress/

please help us fixing this, I've bought the Vantage theme and I've spent a lot of time configuring it, I don't want to start over to use polylang.

Thanks