Hello, this issue is usually caused when you either have a Firewall enabled, OR you do not have 0 - 65535 UDP ports forwarded to your LAN ip.
Try disabling your firewall(s), and port forwarding, if you are unable to fix it, do as stated below.
If you want me to attempt fixing this, please install www.teamviewer.com, and PM me tha ID/Pass that it tells you.
~RedEyes.