Title: headers already sent – ERRORS
Last modified: November 24, 2017

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# headers already sent – ERRORS

 *  Resolved [segmant](https://wordpress.org/support/users/segmant/)
 * (@segmant)
 * [8 years, 5 months ago](https://wordpress.org/support/topic/headers-already-sent-errors-3/)
 * Hi Guys
 * Im getting this error on all 17 of my sites when i update any post/page or custom
   page type.
 * Warning: Invalid argument supplied for foreach() in /htdocs/wp-content/plugins/
   hummingbird-performance/core/modules/class-module-page-caching.php on line 1018
 * Warning: Cannot modify header information – headers already sent by (output started
   at /htdocs/wp-content/plugins/hummingbird-performance/core/modules/class-module-
   page-caching.php:1018) in /htdocs/wp-admin/post.php on line 198
 * Warning: Cannot modify header information – headers already sent by (output started
   at /htdocs/wp-content/plugins/hummingbird-performance/core/modules/class-module-
   page-caching.php:1018) in /htdocs/wp-includes/pluggable.php on line 1216
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fheaders-already-sent-errors-3%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

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

 *  [calumbrash](https://wordpress.org/support/users/calumbrash/)
 * (@calumbrash)
 * [8 years, 5 months ago](https://wordpress.org/support/topic/headers-already-sent-errors-3/#post-9719723)
 * Hi [@segmant](https://wordpress.org/support/users/segmant/),
 * Thank you for using Hummingbird and reporting this issue.
    We are aware of this
   issue and have a fix for this which will be available in the next update. In 
   the meantime could you go to Page Caching settings in your network admin and 
   turn on “Clear full cache when post/page is updated”. Please let us know if this
   resolves the issue.
 * Cheers,
    Calum
    -  This reply was modified 8 years, 5 months ago by [calumbrash](https://wordpress.org/support/users/calumbrash/).
 *  Thread Starter [segmant](https://wordpress.org/support/users/segmant/)
 * (@segmant)
 * [8 years, 5 months ago](https://wordpress.org/support/topic/headers-already-sent-errors-3/#post-9719732)
 * Hi Calum
 * Yes took that step to switch the “Clear full cache when post/page is updated”
   but also found a previous user with the same issue and added the
 *     ```
       if ( ! $metas ) {
           continue;
       }
       ```
   
 * after line 1016 in the /core/modules/class-module-page-caching.php
 * cheers for the quick response

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

The topic ‘headers already sent – ERRORS’ is closed to new replies.

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 * 2 replies
 * 2 participants
 * Last reply from: [segmant](https://wordpress.org/support/users/segmant/)
 * Last activity: [8 years, 5 months ago](https://wordpress.org/support/topic/headers-already-sent-errors-3/#post-9719732)
 * Status: resolved