Title: error_log: Cannot modify header information – headers already sent
Last modified: April 13, 2021

---

# error_log: Cannot modify header information – headers already sent

 *  Resolved [hommealone](https://wordpress.org/support/users/hommealone/)
 * (@hommealone)
 * [5 years, 2 months ago](https://wordpress.org/support/topic/error_log-cannot-modify-header-information-headers-already-sent/)
 * After installing and configuring the plugin, we’re having all sorts of problems
   with our contact forms, and our error log is filling up with this:
 *     ```
       [12-Apr-2021 23:37:45 UTC] PHP Warning:  Cannot modify header information - headers already sent by (output started at /[our_path]/[ourdomain].com/wp-content/plugins/mail-integration-365/classes/mail_integration_365/mail.php:201) in /[our_path]/[ourdomain].com/wp-includes/rest-api.php on line 678
       ```
   
 * Any suggestions?

Viewing 2 replies - 1 through 2 (of 2 total)

 *  [edwardcross](https://wordpress.org/support/users/edwardcross/)
 * (@edwardcross)
 * [5 years, 2 months ago](https://wordpress.org/support/topic/error_log-cannot-modify-header-information-headers-already-sent/#post-14313695)
 * Hi, try ver. 1.6.0 of the plugin, I’ve changed several things so this may have
   resolved this.
 *  Thread Starter [hommealone](https://wordpress.org/support/users/hommealone/)
 * (@hommealone)
 * [5 years, 1 month ago](https://wordpress.org/support/topic/error_log-cannot-modify-header-information-headers-already-sent/#post-14313802)
 * Much better ! Thank you!

Viewing 2 replies - 1 through 2 (of 2 total)

The topic ‘error_log: Cannot modify header information – headers already sent’ is
closed to new replies.

 * ![](https://ps.w.org/mail-integration-365/assets/icon-256x256.png?rev=2817704)
 * [WPO365 | Mail Integration for Office 365 / Outlook](https://wordpress.org/plugins/mail-integration-365/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/mail-integration-365/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/mail-integration-365/)
 * [Active Topics](https://wordpress.org/support/plugin/mail-integration-365/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/mail-integration-365/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/mail-integration-365/reviews/)

 * 2 replies
 * 2 participants
 * Last reply from: [hommealone](https://wordpress.org/support/users/hommealone/)
 * Last activity: [5 years, 1 month ago](https://wordpress.org/support/topic/error_log-cannot-modify-header-information-headers-already-sent/#post-14313802)
 * Status: resolved