node.js - WebRTC: One to one Audio call not working in different machine -

i trying implement 1 one audio call using webrtc (signalling using websockets) . works when try in 1 system using multiple tabs of chrome (localhost). when try hit server machine initial handshakes , call doesn't happen.

but when try change tag , changed constraints video constraints . works if try access other machine (i.e video call works ).

i thought because if firewall when video call worked puzzled .

here code:

// constraints audio stream $scope.constraints = {     audio: {             mandatory: {                 googechocancellation: true             },             optional: []         },     video:false };  navigator.getusermedia = navigator.getusermedia ||     navigator.webkitgetusermedia || navigator.mozgetusermedia;  // success callback of getusermedia(), stream variable audio stream. $scope.successcallback = function (stream) {     if (window.url) {         myvideo.src = window.url.createobjecturl(stream); // converting media stream blob url.     } else {         myvideo.src = stream;     }     //attachmediastream(audiotag, stream);     localstream = stream;     if (initiator)         maybestart();     else         doanswer(); };  // failure callback of getusermedia() $scope.failurecallback = function (error) {     console.log('navigator.getusermedia failed: ', error); }; var initiator, started = false;   $("#call").click(function () {     socket.emit("message", undefined);     initiator = true;     navigator.getusermedia($scope.constraints, $scope.successcallback, $scope.failurecallback); });  var channelready = false; socket.on('message', function (data) {     channelready = true;     if (data) {         if (data.type === 'offer') {             if (!initiator) {                 $("#acceptcall").show();                   $("#acceptcall").click(function(){                       if (!initiator && !started) {                     var pc_config = {                         iceservers: [                      { url: "stun:stun.l.google.com:19302" },                       { url: "turn:numb.viagenie.ca", credential: "drfunk", username: "toadums@hotmail.com"}                      ]                     };                     pc = new webkitrtcpeerconnection(pc_config);                     pc.onicecandidate = onicecandidate;                     pc.onaddstream = onremotestreamadded;                 }                 pc.setremotedescription(new rtcsessiondescription(data));                       $scope.acceptcall();                   });              }         } else if (data.type === 'answer' && started) {             pc.onaddstream = onremotestreamadded;             pc.setremotedescription(new rtcsessiondescription(data));          } else if (data.type === 'candidate' && started) {             var candidate = new rtcicecandidate({                 sdpmlineindex: data.label,                 candidate: data.candidate             });             pc.addicecandidate(candidate);         } else if (data.type === 'bye' && started) {             console.log("bye");         }     } });   function onremotestreamadded(event) {     othersvideo.src = url.createobjecturl(event.stream);   };   var sdpconstraints = {    'mandatory': {      'offertoreceiveaudio': true,      'offertoreceivevideo': false    }  }; function doanswer() {     pc.addstream(localstream);     pc.createanswer(gotdescription,null,sdpconstraints); } function gotdescription(desc) {         pc.setlocaldescription(desc);         socket.send(desc);     }  function maybestart() {     if (!started && localstream && channelready)         createpeerconnection();         pc.addstream(localstream);         started = true;         if (initiator)             docall();     }  $scope.acceptcall = function () {     navigator.getusermedia($scope.constraints, $scope.successcallback, $scope.failurecallback); }  function createpeerconnection() {     var pc_config = {          iceservers: [          { url: "stun:stun.l.google.com:19302" },          { url: "turn:numb.viagenie.ca", credential: "drfunk", username: "toadums@hotmail.com"}          ]     };      pc = new webkitrtcpeerconnection(pc_config);     pc.onicecandidate = onicecandidate;     console.log("created rtcpeerconnnection config:\n" + "  \"" +         json.stringify(pc_config) + "\"."); };   function docall() {     $scope.caller = true;     pc.createoffer(setlocalandsendmessage,null,sdpconstraints); };  function setlocalandsendmessage(sessiondescription) {     pc.setlocaldescription(sessiondescription);     socket.send(sessiondescription); }  function onicecandidate(event) {     if (event.candidate) {         socket.emit('message', {             type: 'candidate',             label: event.candidate.sdpmlineindex,             id: event.candidate.sdpmid,             candidate: event.candidate.candidate         });     } else {         console.log("end of candidates.");     } }