Title: Cannot modify header information error
Last modified: August 19, 2016

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# Cannot modify header information error

 *  Resolved [os0wski](https://wordpress.org/support/users/os0wski/)
 * (@os0wski)
 * [17 years, 1 month ago](https://wordpress.org/support/topic/cannot-modify-header-information-error-2/)
 * This error started to appear when I type my site’s adress in the browser:
 * Warning: Cannot modify header information – headers already sent by (output started
   at /home/osinski/public_html/rap-trojmiasto/wp-includes/default-filters.php:204)
   in /home/osinski/public_html/rap-trojmiasto/wp-includes/pluggable.php on line
   850
 * It appears as well on the homepage as on the admin panel. I didnt changed anything
   in pluggable.php or default-filters.php..
 * How can I fix it?

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

 *  [Samuel B](https://wordpress.org/support/users/samboll/)
 * (@samboll)
 * [17 years, 1 month ago](https://wordpress.org/support/topic/cannot-modify-header-information-error-2/#post-1043610)
 * did you add a plugin recently?
 * [http://codex.wordpress.org/Answers-Troubleshooting#Headers_already_sent](http://codex.wordpress.org/Answers-Troubleshooting#Headers_already_sent)
 *  Thread Starter [os0wski](https://wordpress.org/support/users/os0wski/)
 * (@os0wski)
 * [17 years, 1 month ago](https://wordpress.org/support/topic/cannot-modify-header-information-error-2/#post-1043694)
 * i didnt change anything! it looks a bit like it was hacked or something, look
   at [http://www.rap-trojmiasto.pl](http://www.rap-trojmiasto.pl)
 * another strange thing is that the site works without www but admin panel doesnt
 * anyone can help???
 *  [Samuel B](https://wordpress.org/support/users/samboll/)
 * (@samboll)
 * [17 years, 1 month ago](https://wordpress.org/support/topic/cannot-modify-header-information-error-2/#post-1043802)
 * you fixed it?
 *  Thread Starter [os0wski](https://wordpress.org/support/users/os0wski/)
 * (@os0wski)
 * [17 years, 1 month ago](https://wordpress.org/support/topic/cannot-modify-header-information-error-2/#post-1043926)
 * yes, i uploaded all files again (the newest ones) and it resolved the problem.

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

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

## Tags

 * [header error](https://wordpress.org/support/topic-tag/header-error/)
 * [pluggable.php](https://wordpress.org/support/topic-tag/pluggable-php/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 4 replies
 * 2 participants
 * Last reply from: [os0wski](https://wordpress.org/support/users/os0wski/)
 * Last activity: [17 years, 1 month ago](https://wordpress.org/support/topic/cannot-modify-header-information-error-2/#post-1043926)
 * Status: resolved

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