It looks like your server is waiting for almost 5 seconds (in my test). That typically means there’s a server-side issue going on. Perhaps upgrade your hosting, or ask them to update your server to PHP 7.
Thanks for you reply. I have to fix the server-side thing then.
PHP 7.1.0 is running at the moment. but still old Mysql (MySQL version: 5.1.73), Apache (Apache version: Apache/2.2.27) & Centos (CentOS release 6.8 (Final))
I didn’t know these versions will have so much impact on the server-side responsetime.