Hi Tarek,
The “Cannot modify header information – headers already sent” is commonly known as the “whitespace problem”. The problem is that many editors seem to add additional blanks (spaces) and/or empty lines at the end of a file when you edit it. This so-called whitespace is then sent to the browser when the file is loaded and interferes with the header of a page that the plugin tries to send to the browser, often causing problems such as login problems.
The fix is, obviously, to remove that whitespace from the file. Read the error message carefully. It says “output started at …” followed by a file name and a line number. That is the file (and line) that you need to edit. Ignore the second file name – that is only a file that included the file that has the whitespace. The first file is the one you have to edit, not the second one.
Let us know if this all works out properly for you. The file should not have up to 311 lines.
Best regards,
EWD
Wow! Many thanks.
I followed your instructions… then I got similar error for another file, and I edited the file, then I got about 3 similar errors. After I removed all the blank lines, the wp-admin is now working fine.
Could you tell me what may have happened which added those blank lines at the end of the file?
Let me give you some background… my web hosting expired, then I renewed after 18 days. The person in charge told me that my data is still there, but he cannot guarantee that everything will be back 100% as it was.
Also, about few months ago, my account was jacked, and support send me a notice that it is eating resources, so they did some troubleshooting, and they found the hack and removed it. They told me that I have to update my WordPress and all plugins. Then I requested to suspend my account until I have the time to carryout the update process.
Appreciate your feedback.
Tarek
Hi Tarek,
Functions that send/modify HTTP headers must be invoked before any output is made. Some functions modifying the HTTP header are:
header / header_remove
session_start / session_regenerate_id
setcookie / setrawcookie
Some of the outputs include whitespaces addition before or after the PHP code.
As for the web hosting issue. If you could let us know of the e-mail or the domain name at which it was before, we will retrieve the key code for you.
Best regards,
EWD
Hi,
Today, I checked the website, and I see this error:
Server error
500
I contacted support, and they told me it is because of ultimate product catalog plugin. When we rename it (or disable it), the website works, but plugin is broken of course.
When we check the error_log file, I see the following:
[19-Jan-2016 01:40:31] PHP Fatal error: Cannot redeclare removedir() (previously declared in /home1/adnsense/public_html/wp-content/plugins/ultimate-product-catalogue/Functions/Version_Upgrade.php:40) in /home1/adnsense/public_html/wp-content/themes/CherryFramework/admin/data_management/restore.php on line 38
And the support confirmed that this is the cause of the website not starting.
Appreciate your help to resolve this error.
Tarek
Hi Tarek,
This issue is happening because your theme is declaring a function with the exact same name as a function in our plugin. We had a similar issue recently, which we resolved by changing the name of our function. With that in mind, could you tell me which version of the plugin you’re using? If you’re not using the latest version (3.6.19), could you please update and try again? If that still doesn’t work, please let us know.
Thank you for your reply.
I haven’t updated the plugin since ever I installed it since one year ago. How I can check the current version?
Also, please tell me how to update.
Tarek
If you go to the Plugins section in your WordPress admin, it should say the version number next to our plugin. There should also be an option to update there.
