Added a new template file to a theme – get Call to undefined function error

You are prbebaly using wordpress elements outside the loop
and since its a file ou dont access directly from wordpress
structure but a file you created yourself you should include

<?php
require_once("../../../wp-load.php");
?>

Above the doc type opening tag in sendEMail.php file..

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)