The following error sometimes presents itself when trying to login to the subsite of a WordPress multisite.
ERROR: Cookies are blocked or not supported by your browser. You must enable cookies to use WordPress.
Add the following to your wp-config.php or user-configs.php if you’re on GridPane
define('ADMIN_COOKIE_PATH', '/');
define('COOKIE_DOMAIN', '');
define('COOKIEPATH', '');
define('SITECOOKIEPATH', '');
Some people have reported that the following will also work
define( 'COOKIE_DOMAIN', $_SERVER['HTTP_HOST'] );
Jordan Trask
With 20 years of experience in technology spanning Linux, Data Center Infrastructure, and related services and applications, Jordan consults with small, medium, and large organizations tackling technology problems and needs. With 10 years of experience in WordPress, he’s created Managing WP as a means of dumping his brain on the web.
Jordan operates LMT Solutions providing Technology Consulting Services and We Power WP for WordPress Care Plans and Support.