The RadioServer will not make connections over the WAN.

A common misstake is to configure the server with two different default gateway settings, or a wrong default gateway.

The easiest setup is to use one IP port for a local subnet, where the Network Interfaces are. And the other IP port for the outside connection to the operators. It is only the outside connection that shall have a gateway specified. This is usually the router that connects to the outside world (WAN or the Internet).