Mapped Domain with SSL redirecting to Non SSL

I have installed an SSL cert for one of my mapped domains; however, I'm being redirected to the http:// url when I attempt to load https://

The certificate is installed correctly and working fine according to

I'm using subdomains.
My server is using SNI.
I have an SSL certificate installed on my primary domain that is working fine.

What do I need to do in order for the mapped domain to use the https protocol?