That's weird. Typically I've never seen this issue. Usually, there's no issue with accessing the web panel from another computer on the LAN. You just go to https://192.168.x.x .
Also, ssh always works on the LAN (every time I've install Zentyal), without additional configuration.
Have you make any configuration changes to the Firewall in the Zentyal web interface? Are you should your networking configuration is set up correctly?
What you're describing seem unusual to me.
I believe my network is setup correctly. I have turned the fire wall off for setting it up. It have it left on the default port of 443. I just did dhcp to get the IP while I test it out. And like i said I can ping it and get a response
When trying to connect I get this error
Unable to load the webpage because the server sent no data.
Error code: ERR_EMPTY_RESPONSE
FIXED, The cable was giving it issues. Just had to switch it and reboot the server and its all good now.