Title: Broken e-mails when using Mailgun API
Last modified: April 29, 2026

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# Broken e-mails when using Mailgun API

 *  [Joakim](https://wordpress.org/support/users/noboxjoakim/)
 * (@noboxjoakim)
 * [1 month, 1 week ago](https://wordpress.org/support/topic/broken-e-mails-when-using-mailgun-api/)
 * We have suddenly gotten a lot of headache when using Post SMTP in combination
   with Mailgun API. From having near perfect e-mail deliveries according to mail-
   tester.com we were suddenly down to a horrible 1.9/10 score and started getting
   e-mails ending up in junk across Gmail and Microsoft recipients.
 * After looking through all kinds of DMARC, DKIM and SPF-records according to the
   suggestions from mail-tester.com without any luck I started experimenting by 
   replacing Post SMTP with another SMTP plugin. With that single change, we went
   from a 1.9/10 score to a 9.8/10 score on one of many affected sites. No other
   modifications made, only replacing Post SMTP with another plugin.
 * Compare [https://www.mail-tester.com/noboxsolutions-ZBTF](https://www.mail-tester.com/noboxsolutions-ZBTF)
   with [https://www.mail-tester.com/noboxsolutions-WHBD](https://www.mail-tester.com/noboxsolutions-WHBD)
   to see for yourself. Unknown how long lived the links are.
 * This is potentially a huge issue for a lot of plugin users and could possibly
   affect other tools besides Mailgun as well. I have tried Post SMTP versions 3.9.1,
   3.9.0 and 3.8.0 with the same results. Please look into this and if you need 
   any further details, do feel free to reach out to us.

Viewing 5 replies - 1 through 5 (of 5 total)

 *  Plugin Support [M Aqib Khan](https://wordpress.org/support/users/aqibkhan9/)
 * (@aqibkhan9)
 * [1 month, 1 week ago](https://wordpress.org/support/topic/broken-e-mails-when-using-mailgun-api/#post-18894985)
 * Hi [@noboxjoakim](https://wordpress.org/support/users/noboxjoakim/) ,
 * Thank you for the detailed report.
 * We’ve escalated this to our development team for investigation.
 * If possible, also let us know:
    - Which Mailgun region (EU/US) you’re using
    - Whether you’re using API or SMTP mode
 * We’ll prioritize this and keep you updated as soon as we have findings.
 *  Thread Starter [Joakim](https://wordpress.org/support/users/noboxjoakim/)
 * (@noboxjoakim)
 * [1 month, 1 week ago](https://wordpress.org/support/topic/broken-e-mails-when-using-mailgun-api/#post-18894987)
 * We use EU and API mode. I can look around and see if we have any US based setups
   as well.
 *  Plugin Support [M Aqib Khan](https://wordpress.org/support/users/aqibkhan9/)
 * (@aqibkhan9)
 * [1 month, 1 week ago](https://wordpress.org/support/topic/broken-e-mails-when-using-mailgun-api/#post-18895003)
 * Thanks for confirming.
 *  Thread Starter [Joakim](https://wordpress.org/support/users/noboxjoakim/)
 * (@noboxjoakim)
 * [1 month ago](https://wordpress.org/support/topic/broken-e-mails-when-using-mailgun-api/#post-18899507)
 * [@aqibkhan9](https://wordpress.org/support/users/aqibkhan9/) Any updates on this?
   So far I have had to replace Post SMTP on a number of sites to get the e-mails
   running again. Would prefer not to have to do that across all that has Post SMTP
   running.
 *  Plugin Support [M Aqib Khan](https://wordpress.org/support/users/aqibkhan9/)
 * (@aqibkhan9)
 * [1 month ago](https://wordpress.org/support/topic/broken-e-mails-when-using-mailgun-api/#post-18900059)
 * Hey [@noboxjoakim](https://wordpress.org/support/users/noboxjoakim/)
 * Thanks for following up.
 * The case is currently under review with our internal team, and they’re actively
   investigating it. As soon as we have a concrete, shareable update, we’ll reach
   out to you here.
 * Appreciate your patience on this, we understand the impact and are treating it
   with priority.

Viewing 5 replies - 1 through 5 (of 5 total)

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 * ![](https://ps.w.org/post-smtp/assets/icon-128x128.gif?rev=3209655)
 * [Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App](https://wordpress.org/plugins/post-smtp/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/post-smtp/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/post-smtp/)
 * [Active Topics](https://wordpress.org/support/plugin/post-smtp/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/post-smtp/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/post-smtp/reviews/)

 * 5 replies
 * 2 participants
 * Last reply from: [M Aqib Khan](https://wordpress.org/support/users/aqibkhan9/)
 * Last activity: [1 month ago](https://wordpress.org/support/topic/broken-e-mails-when-using-mailgun-api/#post-18900059)
 * Status: not resolved