Your server is missing the checkdnsrr function which we ask in registration.
This is the error coming from browser console:
PHP Fatal error: Call to undefined function checkdnsrr() in E:\home\viniciux\trekkingbraziltour\Web\wp-content\themes\wpresidence\libs\ajax_functions.php on line 400
This is usually part of the server PHP modules – this is the PHP documentation http://php.net/manual/en/function.checkdnsrr.php
Please ask hosting if they can make sure this function works on server. If not, you will have to modify the code and exclude this request, ALTHOUGH we don’t recommend it since this function checks user email address is valid.