Browser unable to connect local host in ionic

I changed the port number but the browser still can’t find local host,
i think it disconnect after " ionic serve "

Node : v6.9.1
npm  : 3.10.8
OS   : Windows 8.1

How can i fixed it??

What is your ionic info output?
What is your full command you are running and its output? Do you have an error message?

it was the first error
’node’ is not recognized as an internal or an external command.

and i could fixed it.

ionic info
@ionic/cli-utils : 1.19.0
ionic (Ionic CLI) : 3.19.0

local packages:

@ionic/app-scripts : 3.1.5
Ionic Framework    : ionic-angular 3.9.2

Node : v6.9.1
npm : 3.10.8
OS : Windows 8.1

command to run the app is

ionic serve

[OK] Development server running!
Local: http://localhost:8100
DevApp: myApp@8100 on Samar

But it disconnected immediate i can see it on console window