Download WP Rocket – Best WordPress caching plugin

Open the file /wp-rocket/inc/functions/options.php in code editor and go to line 504, replace the block starting with “function rocket_valid_key()” with “return true” exactly in the same way as below:

function rocket_valid_key() {
$rocket_secret_key = get_rocket_option( 'secret_key' );
if ( ! $rocket_secret_key ) {
return true;
}