WEPN uses a feature called UPnP (Universal Plug and Play) supported by almost all routers, in order to automatically open a port and perform port forwarding in your router.
This is necessary in order to allow your WEPN device to communicate and be discovered from the outside world.
If UPnP is disabled on your router, WEPN device won't be able to perform this task and you will need to do this manually yourself.
The following website includes a comprehensive list for every specific router model/make to guide you through port forwarding. Please look up your router make and model and the tutorial to complete port forwarding: