Why is My PHP mail() Function Not Sending Emails?

Why PHP's mail Function Fails to Send Emails

While the provided code should send emails, there are various reasons why it could fail.

1. Check Error Reporting

Ensure that error reporting is enabled to display errors encountered by the code.

2. Verify mail() Function Usage

Confirm that the mail() function is called with the correct syntax and number of parameters.

3. Examine Mail Server Logs

Review your server's mail logs to detect errors or blocks related to email delivery.

4. Check Port Connectivity

Ensure that the SMTP ports 25, 587, or 465 are not blocked on your server or the host's firewall.

5. Avoid Error Suppression

Do not use the error suppression operator (@) when calling mail(), as it conceals potential errors.

6. Validate mail() Return Value

Check the return value of mail() to determine if the email was accepted for delivery. A TRUE return value indicates acceptance, but not necessarily successful delivery.

7. Confirm Host Email Restrictions

Verify with your hosting provider if they limit email sending or block it altogether.

8. Check Spam Filters

Emails from PHP may be filtered as spam. Ensure their legitimacy by following best practices, such as SPF and DKIM authentication.

9. Provide Complete Mail Headers

Missing mail headers, such as "From" and "Reply-To," can cause emails to be rejected.

10. Maintain Proper Syntax in Mail Headers

Incorrect or missing syntax in mail headers can also lead to email rejection.

11. Set Authentic From: Sender

Specify a valid email address as the sender, rather than using user-supplied values.

12. Verify Recipient Address

Confirm that the recipient email address is correct and matches the specified variable.

13. Test Form Configuration

Ensure your form uses the correct method (POST or GET) and specifies the appropriate action pointing to the PHP mailing code.

14. Review Web Hosting Capabilities

Some hosting providers disable email sending. Contact them to verify if sending emails is permitted.

15. Configure Localhost Mail Server

If developing locally, install an email server such as Mercury Mail or use SMTP to send emails.

16. Enable PHP's Custom Mail.log

Create a log file to record the parameters and script used when the mail() function is invoked. This aids in debugging.

17. Utilize Mail Testing Services

Test email delivery and spam status using services like mail-tester.example.

18. Consider Alternative Mailers

Explore PHP mail alternatives such as PHPMailer, SwiftMailer, or PEAR::Mail for greater functionality and flexibility.

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