RD Web services on windows 2012R2 server to Manage IOT Users to their password through Web URL

Hey MS Experts,

I have implemented RDweb server on 2012R2 OS and Domain Controller is running on Server2008R2 in PCI zone, 

https://localhost/RDWeb/Pages/en-US/password.aspx

Above is the URL for IOT Users to access over the SSL from User VLAN.

The issue is Localhost website taking 30-34 second

Configuration - IIS8.5, ASP.Net 4.5, 2012R2 OS with Sept Month Patch, 8 GB RAM, 2 CPU, VM, Pri & Sec DNS IP's our AD server ID. and I have followed below MS article to configure the Web servers

https://social.technet.microsoft.com/wiki/contents/articles/10755.windows-server-2012-rds-enabling-the-rd-webaccess-expired-password-reset-option.aspx

Please suggest. 

Dharmendra