Title: HTTP Headers locks wp_mail
Last modified: November 8, 2023

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# HTTP Headers locks wp_mail

 *  [eitanc](https://wordpress.org/support/users/eitanc/)
 * (@eitanc)
 * [2 years, 6 months ago](https://wordpress.org/support/topic/http-headers-locks-wp_mail/)
 * Hello,
 * I use HTTP Headers along side an email delivery plugin called “POST SMTP”, [https://wordpress.org/plugins/post-smtp/](https://wordpress.org/plugins/post-smtp/)
 * If your plugin, HTTP Headers, is active, the settings page of the “POST SMTP”
   plugin shows a warning like:
 * “
   Postman: wp_mail has been declared by another plugin or theme, so you won’t
   be able to use Postman until the conflict is resolved.**More info that may help**–/
   path/wp-includes/pluggable.php:174
 * Please notice
 * Post SMTP v2 includes and new feature called: **Mailer Type**.
   I recommend to
   change it and **TEST** Post SMTP with the value `PHPMailer`.**ONLY** if the default
   mailer type is not working for you.“
 * If HTTP Headers is inactivated – the above warning is gone.
 * I don’t know of any reason why your plugin will use the mail function of WP.
 * Can you look into this?
    -  This topic was modified 2 years, 6 months ago by [eitanc](https://wordpress.org/support/users/eitanc/).

The topic ‘HTTP Headers locks wp_mail’ is closed to new replies.

 * ![](https://ps.w.org/http-headers/assets/icon-128x128.png?rev=1413576)
 * [HTTP Headers](https://wordpress.org/plugins/http-headers/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/http-headers/#faq)
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 * [Unresolved Topics](https://wordpress.org/support/plugin/http-headers/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/http-headers/reviews/)

 * 0 replies
 * 1 participant
 * Last reply from: [eitanc](https://wordpress.org/support/users/eitanc/)
 * Last activity: [2 years, 6 months ago](https://wordpress.org/support/topic/http-headers-locks-wp_mail/)
 * Status: not resolved