As of April 2018, Apple has discontinued Airport home WiFi router series of devices.
While these devices will continue to function for their owners, they will lack the support and updated firmware releases. Since Airport series used a particular protocol (NAT-PMP) for port forwarding, our software is not able to support adding ports on these devices.
As a result, we have de-prioritized adding support for the Airport devices. Owners with an Apple Airport WiFi router can manually forward the port ranges used by WEPN.
Please feel free to contact WEPN for further instructions and requesting this feature.