Title: Headers not valid.
Last modified: August 20, 2016

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# Headers not valid.

 *  [kelleychambers](https://wordpress.org/support/users/kelleychambers/)
 * (@kelleychambers)
 * [15 years ago](https://wordpress.org/support/topic/headers-not-valid/)
 * When attempting activate the plugin, wordpress throws and error saying that the
   headers are not valid.

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

 *  [Clicknathan](https://wordpress.org/support/users/clicknathan/)
 * (@clicknathan)
 * [15 years ago](https://wordpress.org/support/topic/headers-not-valid/#post-2096127)
 * You could open up the plugin’s file(s) and make sure there are no blank spaces
   before the first <?php and the last ?>. That often does the trick.
 *  [Mladen Gradev](https://wordpress.org/support/users/joe8104/)
 * (@joe8104)
 * [14 years, 5 months ago](https://wordpress.org/support/topic/headers-not-valid/#post-2096402)
 * Clicknathan, you are right. All you have to do if you get “The plugin does not
   have a valid header” error is to edit one file – wp-content/plugins/collapsing-
   links/defaults.php. In line 19 you have to remove the blank space before ?>, 
   save the file and you are done.
 *  [Teleomorph](https://wordpress.org/support/users/teleomorph/)
 * (@teleomorph)
 * [14 years, 1 month ago](https://wordpress.org/support/topic/headers-not-valid/#post-2096416)
 * I still get: “The plugin does not have a valid header.”

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

The topic ‘Headers not valid.’ is closed to new replies.

 * ![](https://s.w.org/plugins/geopattern-icon/collapsing-links.svg)
 * [Collapsing Links](https://wordpress.org/plugins/collapsing-links/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/collapsing-links/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/collapsing-links/)
 * [Active Topics](https://wordpress.org/support/plugin/collapsing-links/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/collapsing-links/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/collapsing-links/reviews/)

 * 3 replies
 * 4 participants
 * Last reply from: [Teleomorph](https://wordpress.org/support/users/teleomorph/)
 * Last activity: [14 years, 1 month ago](https://wordpress.org/support/topic/headers-not-valid/#post-2096416)
 * Status: not resolved