Mail not received on gmail from Contact Form 7

Pls Change PHPmailer Function
Find in root/wp-includes/class-phpmailer.php

private function mail_passthru($to, $subject, $body, $header, $params) {
    if ( ini_get('safe_mode') || !($this->UseSendmailOptions) ) {
        $rt = @mail($to, $this->EncodeHeader($this->SecureHeader($subject)), $body, $header);
    } else {
        $rt = @mail($to, $this->EncodeHeader($this->SecureHeader($subject)), $body, $header, $params);
    }
    return $rt;
  }

replace with

private function mailPassthru($to, $subject, $body, $header, $params)
    {
		$subject= trim(str_replace(array("\r", "\n"), '', $subject));
        if (ini_get('safe_mode') || !($this->UseSendmailOptions)) {
            $rt = @mb_send_mail($to, $subject, $body, $header);
        } else {
            $rt = @mb_send_mail($to, $subject, $body, $header, $params);
        }
        return $rt;
    }

What is its meaning.. I dind understood

The problem not related to contact form 7
problem is from web hosting
after check your mail@address
change “@mail” function to “@mb_send_mail” for fix mail sending

I changed like following

private function mailPassthru($to, $subject, $body, $header, $params)
    {
        $subject= trim(str_replace(array("\r", "\n"), '', $subject));
        if (ini_get('safe_mode') || !($this->UseSendmailOptions)) {
            $rt = @mb_send_mail($to, $subject, $body, $header);
        } else {
            $rt = @mb_send_mail($to, $subject, $body, $header, $params);
        }
        return $rt;
    }

Still not receiving mail

test mail function
testmail.php

<?php
// The message

$sendto = "[email protected]";
$subject = "php mail test";
$message = 'Test message using PHP mail()';
$header = "From: webmaster@".$_SERVER["SERVER_NAME"]."\n";
$header .= "Content-Type: text/html; charset=utf-8\n";

$message = 'Test message using PHP mail()';
$subject='Test';
// Send
if (mail($sendto,$subject,$message,$header, "-fwebmaster@".$_SERVER["SERVER_NAME"]))
{
 echo 'Mail sent!';
} else
{
 echo 'Error! Mail was not sent.';
};
?>