PHPMailer Authentication unsuccessful

Question

When I try to use PHPMailer on windows server 2012 at work to send report emails using SMTP I got Authentication unsuccessful error.

I'm using server administrator account on domain.

I'm very sure of the correction of the password.

check the code below:

require '../PHPMailerAutoload.php';

$mail = new PHPMailer;
$mail->isSMTP();
$mail->SMTPDebug = 2;
$mail->Debugoutput = 'html';
$mail->Host = 'mail.example.com';
$mail->Port = 25;
$mail->SMTPSecure = 'tls';
$mail->SMTPAuth = true;
$mail->Username = "[email protected]";
$mail->Password = "yourpassword";
$mail->setFrom('[email protected]', 'First Last');
$mail->addAddress('[email protected]', 'John Doe');
$mail->Subject = 'PHPMailer SMTP options test';
$mail->msgHTML($html_message);

I got the below response:

SERVER -> CLIENT: 220 exchangeserverhost.com Microsoft ESMTP MAIL Service ready at Tue, 3 Nov 2015 22:19:26 +0300
CLIENT -> SERVER: EHLO exchangeserverhost.com
SERVER -> CLIENT: 250-exchangeserverhost.com Hello 
CLIENT -> SERVER: STARTTLS
SERVER -> CLIENT: 220 2.0.0 SMTP server ready
CLIENT -> SERVER: EHLO exchangeserverhost.com
SERVER -> CLIENT: 250-exchangeserverhost.com Hello 
CLIENT -> SERVER: AUTH LOGIN
SERVER -> CLIENT: 334 
CLIENT -> SERVER: 
SERVER -> CLIENT: 334 
CLIENT -> SERVER: ==
SERVER -> CLIENT: 535 5.7.3 Authentication unsuccessful
SMTP ERROR: Password command failed: 535 5.7.3 Authentication unsuccessful
SMTP Error: Could not authenticate.
CLIENT -> SERVER: QUIT
SERVER -> CLIENT: 221 2.0.0 Service closing transmission channel
SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
Mailer Error: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting

Solution

Problem Solved by changing $mail->SMTPAuth = true; to False.

$mail->SMTPAuth = False;

Comments

[user956584]

!!!! THIS IS SOLUTION !!!!!! mods keep delete my way how so solve this : Open the Microsoft 365 admin center and go to Users > Active users. Select the user, and in the flyout that appears, click Mail. In the Email apps section, click Manage email apps. Verify the Authenticated SMTP setting: unchecked = disabled, checked = enabled. When you're finished, click Save changes.