SMTP & # 8594; ERROR: RCPT not received from server

 require("phpmailer.inc.php");

class sendmail
{
public static function sendAccountActivateMail($to,$subject,&message)
{
    $flg = false;
    try
{
$mail= new PHPMailer(); 
$mail->IsSMTP(); 
$mail->SMTPAuth= true; 
$mail->SMTPSecure= "tls"; 
$mail->Host= "smtp.gmail.com"; 
$mail->Port= 587; 
$mail->Username= "xxx@mydomain.com"; 
$mail->Password= "xxxxxx"; 
$mail->AddReplyTo("info@mydomain.com"); 
$mail->From= "info@mydomain.com"; 
$mail->FromName= "Website"; 
$mail->Subject= $subject; 
$mail->WordWrap= 50; 
$mail->Body = $message; 
$mail->AddAddress($to); 
$mail->Send(); 
}
catch(Exception $e)
    {
        $flg = false;
    }
    return $flg;
}
}

Trying to send mail through phpmailer using smtp. turning on debugging gives me an error:

SMTP → ERROR: RCPT is not received from the server: 550 SMTP AUTH is required to send a message to port 587 SMTP → ERROR: the DATA command is not received from the server: SMTP → NOTIFICATION: EOF is caught during verification if it is connected