How to fix PHPMailer SMTP authentication errors?
28
I'm trying to send emails using PHPMailer but I keep getting SMTP authentication errors like:
- "SMTP Error: Could not authenticate"
- "SMTP Error: Could not connect to SMTP host"
I've double-checked my credentials and SMTP settings. What are the common causes of these errors and how can I resolve them?
50 reputation
1 Answer
0
## 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:
```php
$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. Mailchimp
5. Amazon SES
answered 1 years ago