Unable to send email using Gmail SMTP server through PHPMailer, getting error: SMTP AUTH is required for message submission on port 587. How to fix?

Solution 1:

$mail = new PHPMailer(); // create a new object
$mail->IsSMTP(); // enable SMTP
$mail->SMTPDebug = 1; // debugging: 1 = errors and messages, 2 = messages only
$mail->SMTPAuth = true; // authentication enabled
$mail->SMTPSecure = 'ssl'; // secure transfer enabled REQUIRED for Gmail
$mail->Host = "smtp.gmail.com";
$mail->Port = 465; // or 587
$mail->IsHTML(true);
$mail->Username = "[email protected]";
$mail->Password = "password";
$mail->SetFrom("[email protected]");
$mail->Subject = "Test";
$mail->Body = "hello";
$mail->AddAddress("[email protected]");

 if(!$mail->Send()) {
    echo "Mailer Error: " . $mail->ErrorInfo;
 } else {
    echo "Message has been sent";
 }

This code above has been tested and worked for me.

It could be that you needed $mail->SMTPSecure = 'ssl';

Also make sure you don't have two step verification switched on for that account as that can cause problems also.

UPDATED

You could try changing $mail->SMTP to:

$mail->SMTPSecure = 'tls';

It's worth noting that some SMTP servers block connections. Some SMTP servers don't support SSL (or TLS) connections.

Solution 2:

So I just solved my own "SMTP connection failure" error and I wanted to post the solution just in case it helps anyone else.

I used the EXACT code given in the PHPMailer example gmail.phps file. It worked simply while I was using MAMP and then I got the SMTP connection error once I moved it on to my personal server.

All of the Stack Overflow answers I read, and all of the troubleshooting documentation from PHPMailer said that it wasn't an issue with PHPMailer. That it was a settings issue on the server side. I tried different ports (587, 465, 25), I tried 'SSL' and 'TLS' encryption. I checked that openssl was enabled in my php.ini file. I checked that there wasn't a firewall issue. Everything checked out, and still nothing.

The solution was that I had to remove this line:

$mail->isSMTP();

Now it all works. I don't know why, but it works. The rest of my code is copied and pasted from the PHPMailer example file.