Enable​ ​NAT Traversal (UDP hole punching)

UDP hole punching is one of the most common techniques used to establish UDP connections with systems behind NAT. It is called UDP hole punching because it punches a hole in the firewall of the network which allows a packet from an outside system to successfully reach the desired client on a network using NAT.​ ​If UPnP or manual port forwarding configurations don't help you and your node is still not working, it might be accessible through built-in NAT hole punching capabilities. Try to add the following flag into the service configuration file:​ --nat-port-mapping=false. I​t will skip NAT port mapping and will grant priority to the NAT Traversal.