Concurrent trigger of mails in PHP

I was trying to send mails concretely using php(5.6.21), xampp(3.2.2) 'mail()'. I am getting the below error. I tired in all possible ways and could find out the root cause.

PHP Warning:  mail(): Failed to connect to mailserver at "smtp.tecnotree.com" port 25, verify your "SMTP" and "smtp_port" setting in php.ini or use ini_set() in C:\\xampp\\htdocs\\test\\1.php on line 11, referer:abc.com/test/1.php

Please help me on the same.