I can't get SSL to work

I am trying to three domains working at the moment. All three are a-recored away from Namecheap. They are added to Virtualmin.

Main problem: Links show https:// but not secure?

  1. Virtualmin SSL don’t want to cover subdomains as www. or mail. They stay http? I’ve contacted namecheap, my own VPS host and searched internet for answers. I’ve tried so many different solutions now I can’t even remember them all, but still SSL don’t work?

I am well aware of it is me doing or not doing something, and I need help to understand what it is!