Resolving problem with web emails when using HTTPS with Portrait Dialogue

Product Feature: Installation
This applies to all versions of Portrait Dialogue since PD 5.2


Using Portrait Dialogue -  

Having problems viewing e-mails using the web view functionality.
The top menu line is shown fine, but the content is hidden because of mix of safe and unsafe content.

The source shows the page itself is using HTTPS, but the iframe that should display the content is using HTTP: Web view page (note that you can choose to view unsafe content): Iframe reference:Porblem with web version of emails

Iframe reference:
<div id="ctl07_frameContainerDiv_directRef" class="url-wrapper" style="top: 75px">
<iframe src="" id="ctl07_MessageContentIFrame_directRef" class="web-frame" name="MessageContentIFrame"></iframe>


The "<add key="HostOverride" value=""/>" setting has not been set in the  web.config file for CustomerWebAccess web application.


UPDATED: November 14, 2017
There is a setting for this address in Web.config file for CustomerWebAccess web application (MHCwa).
The setting is the following:
    <!--Overrides the host used when generating absolute URL's (GetApplicationPath() method). Can be used when the Host property used by the web application to get the  server name, is incorrect. The complete URL must be specified complete with http/https and a post number if this is used. (example:>
    <add key="HostOverride" value=""/>
The resolution is to insert the "https" address in the quotes. 
Example :    <add key="HostOverride" value=""/>