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

On some clients' website built using WordPress, there was this error:

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

If you also have a WordPress website where you are seeing the error "Cookies are blocked or not supported by your browser. You must enable cookies to use WordPress" when attempting to login, please find the solution below.

Temporary Solution:

After you get the error "Cookies are blocked or not supported by your browser. You must enable cookies to use WordPress" on the login page, you can simply refresh the page and login again. You should be able to login.

Permanent Solution:

Add the following line at the end of the wp-config.php file.

define('COOKIE_DOMAIN', $_SERVER['HTTP_HOST'] );

That's it.

After adding the above line in wp-config.php file, I do not get the error again.

Related Reference: https://codex.wordpress.org/Editing_wp-config.php