"Warning: Cannot modify header information" when logging in or out

Resolved

Tim

(@thegreentimtam)

Hi, one of my blogs on Multisite install keeps coming up with an error whenever it needs to log in or out.

Here’s the error when logging out:

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-login.php on line 368

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-login.php on line 380

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 697

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 698

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 699

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 700

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 701

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 702

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 705

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 706

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 707

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 708

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 711

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 712

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 713

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 714

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 876

And here’s the error that’s got instead of redirected to wp-login.php:
Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-includes/pluggable.php on line 876

And last, here’s the error when going straight to wp-login.php

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-login.php on line 368

Warning: Cannot modify header information - headers already sent by (output started at /home/jps/public_html/wp-content/themes/artsatjoondalup/functions.php:1) in /home/jps/public_html/wp-login.php on line 380

Followed by the log-in page.

It was working fine a couple of days ago.

Viewing 8 replies - 1 through 8 (of 8 total)

Keyboard_Headaches
(@keyboard_headaches)

10 years, 10 months ago

disable the pluggable plugin and see it that works and let us know. It maybe you have a compatibility issue with that plugin. Also, if your creating the theme yourself from scratch, make sure you included wp-head in the header and wp-footer in the footer. These have screwed me up before with plugins

Krishna
(@1nexus)

10 years, 10 months ago

FTP into your site and temporarily revert to Twenty Twelve theme and see if you can login. Just add -hold to your current theme to revert theme.

Krishna
(@1nexus)

10 years, 10 months ago

Also review:
http://codex.wordpress.org/FAQ_Troubleshooting#How_do_I_solve_the_Headers_already_sent_warning_problem.3F

Thread Starter Tim
(@thegreentimtam)

10 years, 10 months ago

Thanks Krishna! That Codex post was just what I was looking for!

Krishna
(@1nexus)

10 years, 10 months ago

Great! Glad to note that you could solve the problem.

Keyboard_Headaches
(@keyboard_headaches)

10 years, 10 months ago

Nice!

autumnkl
(@autumnkl)

10 years, 10 months ago

Hi, I am getting this same warning when trying to log out of wp admin. http://www.nakedwine.ch
I am thinking that the reason has to do with: “Other issues that might cause that error:
In case you’ve used the function: wp_redirect() or tried to use a header redirect after the header (or any content at all was sent) that error message will pop. Instead use javascript redirection if needed.”

I (stupidly) moved wp files from the server to Mac desktop and then back to server. Then started getting this message. Can you advise in beginner’s language how I can fix this?

Many Thanks!

esmi
(@esmi)

10 years, 10 months ago

Please start by posting your own topic.