• Salesforce.com is changing the hostname of Visual force, Community Builder, Site.com Studio, and content file URLs by removing instance names from URLs.
• This critical update applies to orgs that have a deployed My Domain.
• It will be activated automatically on March 16, 2019. Reference Salesforce Spring '18 Release Notes
• The following new domains are introduced
  • *.visualforce.com
  • *.documentforce.com
  • *.salesforce-communities.com

To remedy the change, the following changes will be required:

1. New SAN certificate needs to be adapted to CDP Integration Server with the following new wildcard entries:

• *.visualforce.<CDP Integartion Server Hostname> (e.g. *.visualforce.cdp.abc.com)
• *.documentforce.<CDP Integartion Server Hostname> (e.g. *.documentforce.cdp.abc.com)
• *.sfdc-communities.<CDP Integartion Server Hostname>(e.g. *.sfdc-communities.cdp.abc.com)

2. Adding corresponding roothosts for the new domains in CDP Integration Server's configfile.xml, under <revproxy:domains>:

        <revproxy:roothost name="visualforce.com" shortform="visualforce">
        </revproxy:roothost>

        <revproxy:roothost name="documentforce.com" shortform="documentforce">
        </revproxy:roothost>

        <revproxy:roothost name="salesforce-communities.com" shortform="sfdc-communities">
        </revproxy:roothost>