Problem in changing network configurations from GUI system admin

[faisalkhan]

hi team,

I am facing a strange problem. I have installed Freepbx 15 and by default it was having ip from dhcp which I changed to static but the machine never came back with that IP. I checked the console no ip was assigned to the machine or it goes to unconfigured. I have assigned the ip address from the cli and restated the machine. things works fine. but now I need to change the static ip to some other ip and when I changed the ip to another static ip the machine is showing nothing instead of this below image.

please help as this is my production server.

[faisalkhan]

however machine takes the ip and I can open up the gui with that ip but on network configuration it shows as the below image.