Error : Cookies are blocked or not supported by your browser

Question

I have a multisite WordPress installation. When I am logged in as a super admin from the main website, and go to the dashboard from the main site into another site, it asks me for login details. When I enter the details, it gives me an error:

ERROR: Cookies are blocked or not supported by your browser. You must enable cookies to use WordPress.

I also added code in wp-config.php:

define('ADMIN_COOKIE_PATH', '/');
define('COOKIE_DOMAIN', '');
define('COOKIEPATH', '');
define('SITECOOKIEPATH', '');

Still the problem occurs, even though cookies are already enabled.

Answer 1

Cookies are enabled per default. By setting

define('ADMIN_COOKIE_PATH', '/');
define('COOKIE_DOMAIN', '');
define('COOKIEPATH', '');
define('SITECOOKIEPATH', '');

you just disabled them by setting the path to an empty string. The ADMIN_COOKIE_PATH per default is the SITECOOKIEPATH followed by wp-admin and the SITECOOKIEPATH is extracted from get_current_site()->path. See source. Just revert what you did and delete the constants from your wp-config.php.

Your actual problem seems that your browser has cookies disabled. Better fix that :)