Using https with Kayako is not as clean as it could be. It has been an ongoing discussion for a few years now.

The process that I have used is to set the admin panel options as described in this Kayako forum thread and then add a redirect in the .htacess file.

In the Kayako admin page go to the General Settings and change the URL from http:// to be https://whatever.your.helpdesk.url.is and save the new setting.

Then go to the Diagnostics page (almost at the bottom of the admin list) and select Rebuild Cache.

Assuming that you are on a Linux platform then editing the .htaccess file will sort the last piece.

What this is doing is redirecting http to https. In the root of the Kayako installation edit the .htaccess file

[text]
RewriteCond %{HTTPS} !=on
RewriteRule .* https://%{SERVER_NAME}%{REQUEST_URI} [R,L]

RewriteEngine On
[/text]
if the .htaccess file already has content this might need to be moved within the file to get it to work correctly just in the event that there is a clash of settings. But, for a blank .htaccess file just add these lines and save it.

Again with assumptions, that the Apache configuration is actually looking at the .htaccess for settings but that is another conversation.

So from the Kayako perspective everything internally is https and if someone does call for http the .htaccess redirects them.