Phpmailer SMTP 500 Error - smtp

Question

I am getting error message when using phpmailer smtp function. I am using php5 and below is the code I used.
require_once("class.phpmailer.php");
$mail = new PHPMailer();
$mail->IsSMTP();
$mail->SMTPDebug = 1;
$mail->SMTPAuth = true;
$mail->Host = 'mail.mydomain.com';
$mail->Port = 21;
$mail->Username = xxx;
$mail->Password = xxx;
$mail->SetFrom($email, $firstname . " " . $lastname);
$mail->AddAddress($contact);
$mail->Subject = $subject;
$mail->Body = $message;
$mail->WordWrap = 50;
$mail->isHTML(true);
$mail->Send();
if(!$mail->Send())
{
echo "email_has_not_been_sent <br><br>";
echo "Mailer Error: " . $mail->ErrorInfo;
$IsSent = 0;
exit;
}
here are the error messages.
SMTP -> ERROR: EHLO not accepted from server: 500 EHLO not understood
SMTP -> ERROR: HELO not accepted from server: 500 HELO not understood
SMTP -> ERROR: AUTH not accepted from server: 500 AUTH not understood
SMTP -> ERROR: RSET failed: 500 RSET not understood
SMTP Error: Could not authenticate. SMTP -> ERROR: MAIL not accepted from server: 500 MAIL not understood

Answer 1

your code looks ok, but I think you're using a port more commonly used for FTP... 25 and 587 are more commonly used as SMTP ports
Some basic telneting should tell you what's going on:
telnet smtp.gmail.com 587
then enter the command EHLO and you will see the welcome message of the gmail SMTP server.
Now try that on your server and you'll see what you get
Then try the same for more common SMTP ports: 25 and 587 and you should see the difference.