Getting Servio to Work with AirPlayer App

I really, really like the Serviio media server and am trying to figure out how to make it work with the AirPlayer app outside of my home network. It works perfectly when I am in my home network. I have tried everything I can think of.
I manually added the device desciption in AirPlayer and did port forwarding on my router, but I cannot get it to work at all. Like I saidm it works perfectly on my home network. When I manually entered the device description in my network, it recognized it as the Serviio media server and all files were accessible. When I switch to LTE, for a while it recognizes the server and gives me an error message that the list could not be loaded and to check my server settings. After 5-10 minutes it is no longer recognized and "UnKnown Media Server" comes up and when I click on it, nothing happens.
Can anyone please help?
Thanks!
I manually added the device desciption in AirPlayer and did port forwarding on my router, but I cannot get it to work at all. Like I saidm it works perfectly on my home network. When I manually entered the device description in my network, it recognized it as the Serviio media server and all files were accessible. When I switch to LTE, for a while it recognizes the server and gives me an error message that the list could not be loaded and to check my server settings. After 5-10 minutes it is no longer recognized and "UnKnown Media Server" comes up and when I click on it, nothing happens.
Can anyone please help?
Thanks!