Fiori launchpad URL is getting started using /n/ui2/flp at ABAP side.

Following URL is getting started and I can see the fiori apps.

http://XXXXXXXXXXXXX:8051/sap/bc/ui5_ui5/ui2/ushell/shells/abap/FioriLaunchpad.html?sap-client=300

but when I am trying to start this URL in IE, initially I am getting following message.

1) Logon is being prepared

2) Then I am getting

This web page is not available

ERR_CONNECTION_TIMED_OU

Please let me know, what could be wrong.