How to fix authentication to smtp server failed WordPress?

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The error message you’re encountering indicates an issue with sending an email using SMTP (Simple Mail Transfer Protocol) in WordPress. Specifically, it’s saying that authentication to the SMTP server failed. Here’s what it means and how to fix it:

  1. Authentication Failure: SMTP servers require authentication to send emails securely. This error message suggests that the WordPress site is trying to send an email via SMTP, but the provided credentials (username and password) are incorrect, or the server doesn’t accept them.

To fix this issue, follow these steps:

  • Check Your SMTP Settings: In your WordPress admin panel, go to “Settings” and then “Email.” Make sure your SMTP settings, including the server, port, username, and password, are correctly configured. Double-check that the credentials match what your SMTP server requires.

  • Use Valid Credentials: Ensure that you’re using the correct username and password for your SMTP server. These are typically provided by your email hosting or SMTP service provider.

  • Use App Passwords (if applicable): Some email services, like Gmail, may require you to use an “App Password” for SMTP. Generate an App Password in your email account settings and use it instead of your regular password.

  • Check Firewall or Security Software: Sometimes, security software or firewall settings on your server can block the connection to the SMTP server. Review your server’s security settings and ensure that outgoing connections on the SMTP port are allowed.

  • Server Configuration: If you’re using a custom SMTP server, make sure it’s configured to allow email sending from your WordPress site. Check if the server is set up to accept incoming SMTP connections from your web server’s IP address.

  • Debug Mode: As the error message suggests, you can enable debug mode in WordPress to get more detailed information about the error. To do this, you can add the following line to your wp-config.php file:


    define('WP_DEBUG', true);

    This will display more specific error messages in your browser, which can help pinpoint the issue.

  • Plugin or Theme Conflict: Sometimes, conflicts with other plugins or your theme can interfere with SMTP email sending. Temporarily deactivate other plugins and switch to a default WordPress theme (e.g., Twenty Twenty-One) to see if the issue persists. If it doesn’t, you may need to identify and resolve conflicts with specific plugins or themes.

  • SSL/TLS Settings: Ensure that your SMTP server’s security settings (SSL/TLS) match the settings in your WordPress configuration. Some servers require secure connections.

After making these adjustments, test your email functionality again. If the issue persists, the error message should provide more specific information that can guide further troubleshooting. If all else fails, consider contacting your hosting provider or email service provider for additional support and guidance.

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