Title: error: QUIT command failed
Last modified: April 3, 2024

---

# error: QUIT command failed

 *  Resolved [brobken](https://wordpress.org/support/users/brobken/)
 * (@brobken)
 * [2 years, 2 months ago](https://wordpress.org/support/topic/error-quit-command-failed/)
 * Hi support team.
   We’re using WP Mail SMTP on our websites without any issues 
   until now; unfortunately all our websites are effected by the following error:
   Mailer: Andere SMTP-serverSMTP Error: Could not authenticate.SMTP server error:
   QUIT command failed
 * We have an integration and are doing a connection to Mailgun through SMTP. It
   occured on websites that we’re previously working without any issues, so it’s
   not an issues with credentials.
    -  This topic was modified 2 years, 2 months ago by [Yui](https://wordpress.org/support/users/fierevere/).
    -  This topic was modified 2 years, 2 months ago by [brobken](https://wordpress.org/support/users/brobken/).

Viewing 1 replies (of 1 total)

 *  Thread Starter [brobken](https://wordpress.org/support/users/brobken/)
 * (@brobken)
 * [2 years, 2 months ago](https://wordpress.org/support/topic/error-quit-command-failed/#post-17548196)
 * We’ve discovered the issue in the meantime. 
   Mailgun is only allowing an IP Allowlist
   now also for SMTP connections as well instead of just their API.For further reference:
   [https://help.mailgun.com/hc/en-us/articles/360012244474-IP-Allowlist](https://help.mailgun.com/hc/en-us/articles/360012244474-IP-Allowlist)

Viewing 1 replies (of 1 total)

The topic ‘error: QUIT command failed’ is closed to new replies.

 * ![](https://ps.w.org/wp-mail-smtp/assets/icon-256x256.png?rev=1755440)
 * [WP Mail SMTP by WPForms - The Most Popular SMTP and Email Log Plugin](https://wordpress.org/plugins/wp-mail-smtp/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/wp-mail-smtp/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/wp-mail-smtp/)
 * [Active Topics](https://wordpress.org/support/plugin/wp-mail-smtp/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/wp-mail-smtp/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/wp-mail-smtp/reviews/)

 * 1 reply
 * 1 participant
 * Last reply from: [brobken](https://wordpress.org/support/users/brobken/)
 * Last activity: [2 years, 2 months ago](https://wordpress.org/support/topic/error-quit-command-failed/#post-17548196)
 * Status: resolved