Title: Incorrect Mailbox Syntax Configuration Error
Last modified: December 20, 2018

---

# Incorrect Mailbox Syntax Configuration Error

 *  [bowqtr](https://wordpress.org/support/users/bowqtr/)
 * (@bowqtr)
 * [7 years, 4 months ago](https://wordpress.org/support/topic/incorrect-mailbox-syntax-configuration-error/)
 * Appreciate any guidance on the following page. If you review this screenshot 
   it shows that the From address and Reply-To has an incorrect mailbox syntax. 
   However these look correct to me. How can I resolve these issues? Many thanks
   in advance.
 * [http://prntscr.com/lxj0pd](http://prntscr.com/lxj0pd)
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fincorrect-mailbox-syntax-configuration-error%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 4 replies - 1 through 4 (of 4 total)

 *  [John](https://wordpress.org/support/users/johncharlton/)
 * (@johncharlton)
 * [7 years, 4 months ago](https://wordpress.org/support/topic/incorrect-mailbox-syntax-configuration-error/#post-11013260)
 * Following as I’m having similar problems with the latest validator.
 * Cc: [mickey@mouse.com](https://wordpress.org/support/topic/incorrect-mailbox-syntax-configuration-error/mickey@mouse.com?output_format=md)
   
   Reply-To: [your-email]
 * Warning: Invalid mailbox syntax is used in the Reply-To field.
 * Strange, because Reply-To: validates on other forms on the same site using the
   same code. Never been a problem in the past.
 *  [Neil Murray](https://wordpress.org/support/users/buzztone/)
 * (@buzztone)
 * [7 years, 4 months ago](https://wordpress.org/support/topic/incorrect-mailbox-syntax-configuration-error/#post-11018872)
 * [@bowqtr](https://wordpress.org/support/users/bowqtr/)
 * `From: .. <[Email]>` is now very risky – your CF7 emails are likely to be rejected
   as spam by email servers around the world, without you knowing about it. The 
   [Configuration Validator](https://contactform7.com/configuration-validator-faq/)
   is warning of this serious issue.
 * Using an email from [the domain where your website is hosted in the From: field](https://blog.cf7skins.com/use-a-suitable-from-address-in-contact-form-7/#correct-from-address)
   is the simplest safe option.
 * I believe the error in Additional Headers will go away after you fix the _From:
   field warning_.
 *  [John](https://wordpress.org/support/users/johncharlton/)
 * (@johncharlton)
 * [7 years, 4 months ago](https://wordpress.org/support/topic/incorrect-mailbox-syntax-configuration-error/#post-11019825)
 * I agree Neil Murray, which is why I use
    From: [your-name] <fhandler@mouse.com
   > but I still get that error message on the Additional Headers.
 * Perhaps I need to start a new thread as my issue may be different from bowqtr’s
   issue.
 *  [Neil Murray](https://wordpress.org/support/users/buzztone/)
 * (@buzztone)
 * [7 years, 4 months ago](https://wordpress.org/support/topic/incorrect-mailbox-syntax-configuration-error/#post-11020493)
 * > Perhaps I need to start a new thread as my issue may be different from bowqtr’s
   > issue.
 * Definitely – answering your question here is not appropriate as it would take
   over [@bowqtr](https://wordpress.org/support/users/bowqtr/)’s post.

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘Incorrect Mailbox Syntax Configuration Error’ is closed to new replies.

 * ![](https://ps.w.org/contact-form-7/assets/icon.svg?rev=2339255)
 * [Contact Form 7](https://wordpress.org/plugins/contact-form-7/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/contact-form-7/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/contact-form-7/)
 * [Active Topics](https://wordpress.org/support/plugin/contact-form-7/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/contact-form-7/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/contact-form-7/reviews/)

 * 4 replies
 * 3 participants
 * Last reply from: [Neil Murray](https://wordpress.org/support/users/buzztone/)
 * Last activity: [7 years, 4 months ago](https://wordpress.org/support/topic/incorrect-mailbox-syntax-configuration-error/#post-11020493)
 * Status: not resolved