Warning: Cannot modify header information - headers already sent by

Question

Hi there I have seen similar problems on the net about this issue but the resolutions I have tried have not worked.

i'm developing a word-press site for a client I have done this before without issue. However, this time when I uploaded the template to my test server for the clients viewing I encountered these errors.

Warning: Cannot modify header information - headers already sent by (output started at /homepages/0/d682858018/htdocs/clickandbuilds/test/wp-includes/option.php:1) in /homepages/0/d682858018/htdocs/clickandbuilds/test/wp-includes/option.php on line 808

Warning: Cannot modify header information - headers already sent by (output started at /homepages/0/d682858018/htdocs/clickandbuilds/test/wp-includes/option.php:1) in /homepages/0/d682858018/htdocs/clickandbuilds/test/wp-includes/option.php on line 809

I have gone to the file and the lines it is referring to are ;

    // The cookie is not set in the current browser or the saved value is newer.
$secure = ( 'https' === parse_url( admin_url(), PHP_URL_SCHEME ) );
setcookie( 'wp-settings-' . $user_id, $settings, time() + YEAR_IN_SECONDS, SITECOOKIEPATH, null, $secure );
setcookie( 'wp-settings-time-' . $user_id, time(), time() + YEAR_IN_SECONDS, SITECOOKIEPATH, null, $secure );
$_COOKIE['wp-settings-' . $user_id] = $settings;

Would appreciate some guidance as to what is causing the error and how to fix it.

Things I have tried;

• *eliminating white space
• *removing ?>
• *combing through code in function.php and removing whitespace.
• *reinstalling wordpress.

Some people have marked this question as similar to another question but as I have mentioned this is different it's something to do with the template. It works fine locally

Answer 1

尝试通过文件管理器上传模板，然后在wp-admin中将其激活。

Answer 2

Found the issue when I actually viewed the code in a separate editor it highlighter a space before the opening

Thanks for everyones comments.

Answer 3

for me this error was in my Prestashop site(v 1.6.0.6) homepage and solved by lowering site php version from 5.6 to 5.3 in cpanel => MultiPHP Manager section.

so if you prefer more detail and manual editing, check .htaccess file and add following line to it

AddHandler application/x-httpd-php53.php