w3 total cache not detecting memcached

I am on Plesk 12.5 with CentOS 7. Memcached installed via EPEL repo.

[root@plesk ~]# rpm -qa|grep memca
libmemcached-devel-1.0.16-5.el7.x86_64
memcached-1.4.15-9.el7.x86_64
libmemcached-1.0.16-5.el7.x86_64

[root@plesk ~]# systemctl status memcached.service
● memcached.service - Memcached
Loaded: loaded (/usr/lib/systemd/system/memcached.service; enabled; vendor preset: disabled)
Active: active (running) since Mon 2016-04-18 17:27:55 SGT; 4min 24s ago
Main PID: 9402 (memcached)...

w3 total cache not detecting memcached