Social Engineering Tools not working outside LAN

Hey guys, I have one problem with the social toolkit. I've made a powershell and made .bat file out of it, when I send it to my LAN computers it works perfect, but when I send it to my friends PC to test it out it doesn't connects to my IP address (to my pc), I don't have it in my sessions.

I'm using Kali linux over VirtualBox and I'm creating Powershell Attack Vectors / Alphanumeric

>setting the correct LHost

>setting the correct LPort

and then using handler exploit to view the sessions. As I said when I used it on my desktop PC (Windows) it works, but when my friend use it on his PC who's outside LAN it doesn't detects it. :S

Any solutions?

Thank you in advance