licence on a home networked server ?

i want to use the demo licence on a home networked server just for testing purposes, when i try to validate the demo licence i get this message ;
The IP address (19#.#.#.#) of this server was not set!
this is my internal ip of the computer.
as this is my internal ip the validate licence goes no further as my licence is registered to my external WAN IP as i thought the licence would not use private ip.

Could you correct me where i am going wrong, i have setup on a separate PC, should the demo licence have the internal ip of the PC ? or external ?

Thank you

Gary

now sorted

Today is my first time installing interworx and I had a similar issue to this. Turns out all I needed to do was activate the license via the process at http://www.interworx.com/support/docs/iworx-cp/install/activate-license I’m posting this in case it’s helpful to anyone else. This was for a demo license on a local 192.168.* VPS.