Hello Oriolo, by Console do you mean the WordPress administration (WP-Admin > Comments)?
When you reply to a comment in that section your email is not at all validated. To give you more technical details when the reply button is clicked (in the WP Backend) the wp_ajax_replyto_comment() function handles the commenting. This function does not validate the email using
is_email() which means this plugin never comes into the picture.
That error is because your host (Beget I guess) is slow and the connection times out. Have a look at the Nginx version numbers.
C:\Users\A.Jesin>curl -I -s http://oriolo.ru/ | find /i "nginx"
C:\Users\A.Jesin>curl -I -s https://api.mailgun.net/v2/address/validate | find /i "nginx"
Disable this plugin and check if this error persists.
Thanks a lot for blogging about this plugin :-)