Webrtc does not work over other networks.. STUN,TURN Server Already Set up

Problem: My webrtc works totally fine from localhost environment or in the same wifi, but it unfortunately fails over distinct networks. I have searched extensively about this subject across stackoverflow but none have provided me a working solution.

Platform: Android => Firefox or Chrome (Android creates offer)

I have tried: -Using stun:stun.l.google.com:19302 server -Using public turn servers -Hosting my own turn server through VPS and Coturn -Hosting my own stun server similarly -HAVE ALREADY VERIFIED my own stun/turn servers on https://webrtc.github.io/samples/src/content/peerconnection/trickle-ice/. They all return correct sfrlx and relay ice candidates, respectively.

If I run it on chrome, the console does not raise any errors. If I run it on firefox, however, the console does fire : "ICE FAILED, see about:webrtc for more details"

And here is my about:webrtc log https://pastebin.com/jLHVFGxH

Some more tabular informations: https://i.stack.imgur.com/oInn0.png https://i.stack.imgur.com/FSGYx.png

My iceServer configuration:

   var connection = new RTCPeerConnection({
                iceServers: [{
                        urls:'stun:stun.l.google.com:19302'
                    },
                    {
    url: 'turn:64.227.18.138:3478',
    credential: '*****',
    username: '******'
}]
            })

Now on android side:

   List<PeerConnection.IceServer> iceServers = new ArrayList<>();

        iceServers.add(PeerConnection.IceServer.builder("stun:stun.l.google.com:19302").createIceServer());
        iceServers.add(PeerConnection.IceServer.builder("turn:64.227.18.138:3478").setUsername("*****").setPassword("*******").createIceServer());