SMTP Error 451-4.4.2: Timeout – Closing Connection

Overview

The ‘error 451-4.4.2 timeout’ issue often occurs on sites using Gmail’s API to send emails. This error indicates that while the connection between your SMTP server and the recipient’s email server was established successfully, it closed before sending the email due to a timeout.

Causes

These are some of the common causes of the ‘error 451-4.4.2 timeout’ error. Below we’ve highlighted the most common causes:

  1. Network issues: Unstable or slow internet connections can lead to timeouts.
  2. Incorrect SMTP configuration: Using the wrong port or settings can cause connection problems.
  3. Server overload: High traffic or resource constraints on either the sending or receiving server.
  4. Firewall restrictions: Your hosting server’s firewall may be blocking SMTP requests.

Solution

To resolve the ‘error 451-4.4.2 timeout’, first, make sure your connection is stable and fast enough to complete the email-sending process.

Since this error can be temporary due to server overload, we suggest waiting and retrying after a while.

If the error persists, double-check your SMTP server settings and ensure they’re properly configured. Also, if you’re using the Other SMTP mailer, consider switching to one of the available mailers to improve your site’s email deliverability.

Note: Want to explore available email service providers WP Mail SMTP supports? Be sure to check out our complete guide to WP Mail SMTP mailers.

Another solution to the error is temporarily disabling firewall protection from your site’s hosting provider. Some web hosts have security settings that block requests from SMTP servers. You may need to contact your web host if you’re at all unsure where to locate this setting.

That’s it! Now you know how to troubleshoot and fix the ‘Error 451-4.4.2: Timeout – closing connection’ issue.

Want to improve your site’s email deliverability? Consider configuring an additional connection to use as a backup mailer when your primary connection fails to send emails.