How to Automatically Resend a Failed Email

Would you like to automatically resend failed emails from your WordPress site? Doing so can help make sure users receive important communications without you having to manually retry emails after errors.

In this article, we’ll share which mailers in WP Mail SMTP automatically resend failed emails.


Your mailer handles resending failed emails, rather than WP Mail SMTP itself. This functionality only works for “soft-bounced” emails, such as those that cannot be delivered due to server-related issues on the recipient’s end, or full inboxes.

Below, we’ve explained how each of the mailers that support this option automatically resend failed emails.

Note: For more information on each of the mailers before, see their descriptions in our complete guide to mailer options in WP Mail SMTP.

SMTP.com

If an email cannot be delivered, SMTP.com will attempt to resend it continuously for 24 hours.

After that time, if the email still cannot reach the recipient’s inbox, you’ll receive a bounce-back message reading, “Exceeded max tries without delivery.”

Sendinblue

Sendinblue attempts to resend failed emails 3 times over a period of 36 hours. After those attempts, it will stop resending the email.

Note: Each time Sendinblue attempts to resend a failed email, it counts towards your monthly email limit. See its official documentation on this topic for more details.

Mailgun

When using Mailgun, failed emails are resent over a period of 8 hours at the following intervals:

  • 10 minutes after the initial email
  • 20 minutes after the initial email
  • 35 minutes after the initial email
  • 1 hour after the initial email
  • 2 hours after the initial email
  • 4 hours after the initial email
  • 8 hours after the initial email

After this series of attempts, Mailgun will stop trying to resend the email.

Note: For more details on automatic resending of failed emails in Mailgun, see its user manual.

SendGrid

SendGrid attempts to resend emails that fail due to a soft bounce for 72 hours. After that period, if the email cannot be sent successfully, it will be blocked from resending again.

Note: For more details, see SendGrid’s post on email events.

Postmark

When a soft bounce occurs, Postmark will make multiple attempts to resend the failed email.

After it stops trying to send the email again, its status will be listed as “Soft Bounce” or “Undeliverable” in the Activity section of your Postmark account. You can look under More Details¬†for additional information.

Note: For additional information on how Postmark handles soft bounces, see its documentation on this topic.

Amazon SES

If Amazon SES fails to deliver an email from your site, it will try resending the failed email multiple times. You should receive a notification when it stops trying to deliver the email.

Note: Attempts to resend emails may count towards your monthly quota. For more details, see Amazon’s documentation on this topic.

Zoho Mail

Zoho Mail moves failed emails to a Retry Queue, from which it will automatically resend them for a period of days. You’ll receive an email notification letting you know how many more days it will attempt to resend the email.

You can also view your Retry Queue in your Zoho Mail account. See the documentation on this topic for details on how to access it.

That’s it! Now you know which WP Mail SMTP mailers resend failed emails automatically.

Next, would you like to learn more about monitoring your email logs for errors? See our guide to enabling email logging in WP Mail SMTP for all the details.