Warning: Cannot modify header information - headers already sent

Question

 

My website worked perfectly.

But then I upgraded my vps with x-cache, mysql 5.5, and also

.htaccess cache time 

 

# 1 MONTHS

<FilesMatch "\.(jpg|jpeg|png|gif|swf|ico)$">

Header set Cache-Control "max-age=2419200, public"

ExpiresDefault "access plus 1 month"

SetOutputFilter DEFLATE

</FilesMatch>

 

 

<FilesMatch "\.(css|js)$">

Header set Cache-Control "max-age=604800, public"

ExpiresDefault "access plus 1 week"

SetOutputFilter DEFLATE

</FilesMatch>

 

The website still works perfectly but when I log with admin account, and access admin panel I get this error

Warning: Cannot modify header information - headers already sent by (output started at /home/xxxxxxx/public_html/qa-include/qa-theme-base.php:1) in /home/xxxx/public_html/qa-include/qa-page.php on line 329

 

The error disappears if i click on other page rather than admin panel.

 

it seems that it already gets a header when i click admin panel but where?

 

I restarted the vps but the error is still there

MySQL: 5.4.13

PHP: 5.5.30-cll

 

And I also tried to remove all the sessions in /tmp

Answer 1

Usually this error occurs when you rendering anything ( HTML ) before content type or that couldn be a reason of encoding.

Many expewrts here already answered this question. http://www.question2answer.org/qa/14468/warning-header-information-headers-already-warning-message

You can check article about it as well here http://www.q2amarket.com/q2a-tips-n-tricks/warning-cannot-modify-header-information-headers-already-sent-by/

Comments

I found the issue, it's quite stupid.

In qa-theme-base.php
I modified by accident  |     <?php           where " | "is the beging of line
I modified it back |<?php    at the begining of line with no space and it works..

3 hours spent..

---

Yeah, There should not be any character or a space. Good you resolved.

Answer 2

I found the issue, it's quite stupid.

In qa-theme-base.php
I modified by accident  |     <?php           where " | "is the beging of line
I modified it back |<?php    at the begining of line with no space and it works..

3 hours spent..

Answer 3

I experienced the problem after I updated of of the php files using wrong text encoding. After changing it to UTF-8 without BOM the warnings disappeared.