How to fix PHPMailer SMTP authentication errors?

SMTP Error: Could Not Authenticate in PHPMailer

This error occurs when PHPMailer cannot authenticate with the SMTP server.

SMTP Common Causes:

1. Incorrect SMTP credentials (username, password)

2. Incorrect SMTP settings (host, port, encryption)

3. SMTP server requires additional authentication mechanisms (e.g., CRAM-MD5)

4. Email account authentication issues (e.g., account locked, expired password)

5. PHPMailer configuration issues

Troubleshooting Steps:

1. Verify SMTP credentials:

    - Double-check username and password

    - Ensure correct email account credentials

2. Verify SMTP settings:

    - Host: e.g., (your host link)

    - Port: e.g., 587

    - Encryption: e.g., TLS

3. Check SMTP server requirements:

    - CRAM-MD5 or other authentication mechanisms

    - SSL/TLS certificates

4. Test SMTP connection using:

    - Telnet: `telnet smtp_host smtp_port`

    - PHPMailer's debug mode: `$mail->SMTPDebug = 2;`

5. Update PHPMailer configuration:

    - Set correct SMTP credentials

    - Set correct SMTP settings

PHPMailer Configuration:

$mail->isSMTP();

$mail->Host = '(your host link)';

$mail->Port = 587;

$mail->SMTPSecure = 'tls';

$mail->SMTPAuth = true;

$mail->Username = 'your email';

$mail->Password = 'your email password';

Popular SMTP Services:

1. Gmail SMTP

2. SendGrid

3. Mailgun

4. Amazon SES

5. Microsoft Outlook