Title: Authentication failed
Last modified: June 15, 2021

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# Authentication failed

 *  Resolved [marcustheo](https://wordpress.org/support/users/marcustheo/)
 * (@marcustheo)
 * [4 years, 11 months ago](https://wordpress.org/support/topic/authentication-failed-26/)
 * I’ve set up to use an Office365 account to send the emails on my website. The
   account details are correct, the account is set to have Authenticated SMTP enabled,
   but sending is failing. I get the following error message:
 *     ```
       220-blackwell.dnshostnetwork.com ESMTP Exim 4.94.2 #2 Tue, 15 Jun 2021 17:20:45 +0100 
       220-We do not authorize the use of this system to transport unsolicited, 
       220 and/or bulk e-mail.
       ```
   
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fauthentication-failed-26%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 3 replies - 1 through 3 (of 3 total)

 *  [Tim](https://wordpress.org/support/users/tneville/)
 * (@tneville)
 * [4 years, 11 months ago](https://wordpress.org/support/topic/authentication-failed-26/#post-14564002)
 * Hi [@marcustheo](https://wordpress.org/support/users/marcustheo/),
 * You are not connecting to Office 365, as `blackwell.dnshostnetwork.com` is a 
   cPanel server – not Office 365 SMTP.
 * Please paste a copy of your Post SMTP diagnostics log in your next reply, but
   it is likely your configuration is incorrect.
 * Kind Regards,
    Tim
 *  Thread Starter [marcustheo](https://wordpress.org/support/users/marcustheo/)
 * (@marcustheo)
 * [4 years, 11 months ago](https://wordpress.org/support/topic/authentication-failed-26/#post-14564409)
 * Thanks for replying Tim. I’ve completed all the fields, so I’m not sure I’ve 
   done wrong in configuration. Anyway, here’s the diagnostics
 *     ```
       Mailer: postsmtp
       HostName: napierwatt.co.uk
       cURL Version: 7.74.0
       OpenSSL Version: OpenSSL/1.1.1k
       OS: Linux blackwell.dnshostnetwork.com 3.10.0-962.3.2.lve1.5.32.el7.x86_64 #1 SMP Fri Feb 28 07:18:51 EST 2020 x86_64
       PHP: Linux 7.2.34 C
       PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=No, mcrypt=No, zlib_encode=Yes
       WordPress: 5.5.5 en_US UTF-8
       WordPress Theme: Flatsome Child
       WordPress Plugins: Alfred, the Assistant, Contact Form 7, Cookie Notice & Compliance for GDPR / CCPA, Duplicate Page, Insert Headers and Footers, Nextend Social Login, Password Protected, Post SMTP, Property Hive Stamp Duty Calculator, Really Simple SSL, Slider Revolution Exploding Layers Add-On, Slider Revolution Typewriter Effect, Slider Revolution, Spotlight - Social Media Feeds, WooSidebars, Yoast SEO, WP Property Feed, WPForms
       WordPress wp_mail Owner: /home/napierwattco/public_html/wp-content/plugins/post-smtp/Postman/PostmanWpMailBinder.php
       WordPress wp_mail Filter(s): wp_staticize_emoji_for_email, PostsmtpMailer->get_mail_args
       WordPress phpmailer_init Action(s): wpcf7_phpmailer_init, PostsmtpMailer->phpmailer_smtp_init
       Postman: 2.0.23
       Postman Sender Domain (Envelope|Message): napierwatt.co.uk | napierwatt.co.uk
       Postman Prevent Message Sender Override (Email|Name): No | No
       Postman Active Transport: SMTP (smtp:none:plain://smtp.office365.com:587)
       Postman Active Transport Status (Ready|Connected): Yes | Yes
       Postman Deliveries (Success|Fail): 12 | 19
       ```
   
 *  [Tim](https://wordpress.org/support/users/tneville/)
 * (@tneville)
 * [4 years, 11 months ago](https://wordpress.org/support/topic/authentication-failed-26/#post-14568092)
 * Hi [@marcustheo](https://wordpress.org/support/users/marcustheo/),
 * Your security configuration is not correct.
 * Change ‘Security’ from ‘None’ to ‘STARTTLS’.
    Change ‘Authentication’ from ‘Plain’
   to ‘Login’.
 * Then you can re-test and you should be okay. 🙂
 * Kind Regards,
    Tim

Viewing 3 replies - 1 through 3 (of 3 total)

The topic ‘Authentication failed’ is closed to new replies.

 * ![](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/)
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 * 3 replies
 * 2 participants
 * Last reply from: [Tim](https://wordpress.org/support/users/tneville/)
 * Last activity: [4 years, 11 months ago](https://wordpress.org/support/topic/authentication-failed-26/#post-14568092)
 * Status: resolved