Elementor contact form doesn’t work: “Oops! I cannot send this email!”

My contact page has the default Elementor contact form, but it doesn’t work.

I really don’t know where could be the problem. Could you help me?

Edit:

I fixed by installing sendmail (needed by Elementor contact form) following this guide: https://www.digitalocean.com/community/questions/php-mail-function-enable