I have an old setup (Ubuntu 12.04.5 LTS (Precise Pangolin)) ISPConfig 3.1.7p1. First try setting up SSL for one website.Following various tutorials and threads Letsencrypt has now been validated and certificate generated. However I still can't browse using https it just times out. For letsencrypt to work do I have to be using the ISPConfig DNS server as I am using the domain registrars DNS ?
That's how far I got before giving up. The reason most people here will also give up is because there is simply too many ways to go wrong with something as complex as 3rd party SSL (on top of "something" that relies on "something" else configured by some 3rd party who used to work here. I recommend using one of Till Brehm's Perfect Server configs to build a new server (min. 16.04 or Debian 8) that way you have an actual build document that you can always refer to. This documentation is actually the reason why I started using "Perfect Server" guides. Not because of the "tutorial" (although that is also fantastic.) After you are done with the installation copy the "documentation" to your servers /root and use that as basis for all future modifications (which you will of-course faithfully document after each time you add/modify anything. You may now stop laughing!)
Maybe you should just start with the basics: 1) Is port 443 open in the firewall, if you use one? 2) Is the server behind a router? If yes, did you forward port 443 from router to server and opened that port in the router firewall? 3) is apache or nginx listening on port 443 at all?
