VM Activation problem when using Internal Virtual Switch mode

Hello,

I have setup Windows 2012 R2 Standard Version host machine.  Hyper-V setup successful. Host machine already activate license.

I have got a problem is when VM connecting with Internal virtual Switch.  It will not able to process Windows activation.  If it connected using External Virtual Switch, it can successful do windows activation.  However, using External Virtual Switch, one more WAN IP will be used.

I am using ICS method to share the network interface to Internal Virtual Switch.

Is it what problem and how to resolve it?

Thanks!