Hi @subwebsites ,
The Object cache setup has two parts.
One is installing the memcached server via SSH, and another is enabling the PHP extension which allows the PHP applications such as WordPress to communicate with WordPress.
While it looks like your Memcached extension is enabled on PHP, The Connection Failed result is because of the Memcached Server not installed or configured.
The script given in the above response as @qtwrk mentioned, is for testing if memcached server is installed.
You can create it inside your public_html, and then access it from the frontend, You can create it at public_html/test.php, and then try to access yourdomain.com/test.php.
Post the result, This will allow you to confirm if memcached server is installed.
If it is not installed, you need to setup memcached server or ls-memcached(it is faster) on your server via SSH to make it work. This is how you can do it – https://www.litespeedtech.com/support/wiki/doku.php/litespeed_wiki:lsmcd:installation