Title: Cannot modify headers information
Last modified: October 23, 2017

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# Cannot modify headers information

 *  [tomlandis](https://wordpress.org/support/users/tomlandis/)
 * (@tomlandis)
 * [8 years, 7 months ago](https://wordpress.org/support/topic/cannot-modify-headers-information-2/)
 * I am getting the error below, not too sure why. My code says:
 * if (!isset($_SESSION)) session_start();
 * (This code is triggered by a snippet.)
 * Thank you, both for the plug-in and for the support!
 * —-
    ERROR:
 * Warning: Cannot modify header information – headers already sent by (output started
   at /opt/bitnami/apps/wordpress/htdocs/wp-includes/formatting.php:5079) in /opt/
   bitnami/apps/wordpress/htdocs/wp-content/plugins/wp-native-php-sessions/callbacks.
   php on line 35
    -  This topic was modified 8 years, 7 months ago by [tomlandis](https://wordpress.org/support/users/tomlandis/).
      Reason: (typo)
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fcannot-modify-headers-information-2%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

The topic ‘Cannot modify headers information’ is closed to new replies.

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 * 0 replies
 * 1 participant
 * Last reply from: [tomlandis](https://wordpress.org/support/users/tomlandis/)
 * Last activity: [8 years, 7 months ago](https://wordpress.org/support/topic/cannot-modify-headers-information-2/)
 * Status: not resolved