ERROR: Cookies are blocked or not supported by your browser

Sometimes, when you try to log in to your site, you may encounter this error:

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

This problem can have many different causes, some of which can be related to caching.

Are cookies enabled in the browser?

First of all, you should make sure that cookies are in fact enabled in the browser, and they’re not being blocked.

Does your site have a custom login page?

WP Rocket  does not cache the default WordPress login/logout URLs (wp-login.php). However, if you use custom URLs, WP Rocket will cache them unless you manually exclude them from the cache. 

Here’s how that works:
Exclude pages from the cache

None of the above?

If none of the above fixed the issue for you, please consult  one of the many public support threads on this topic.