Ubuntu 16.04, ispconfig3 Won't link to site I created

Hi,

I just installed Ubuntu 16.04 Server on a desktop machine in my basement and I installed a LAMP setup according to:

https://www.howtoforge.com/tutorial/...and-ispconfig/

Everything SEEMED to go well. I was able to set up a website using ispconfig3, create an email address, type 172.16.1.38/roundcube into the browser in my laptop, and log into Roundcube and send an email that actually arrived at its destination.

However...

When I type the server private ip into my browser, I get the Apache welcome page, everything is great. But if I go into ispconfig, go to "Sites", and click on the link to the site I created, I get an "unable to Coect" error. "Firefox can't establish a coection to the server at..."

Any ideas on why this might be happening? I disabled ufw so that shouldn't be it. Appreciate your help, thanks.