diff --git a/app.js b/app.js
index bad26fe..4b73ec5 100644
--- a/app.js
+++ b/app.js
@@ -164,7 +164,10 @@ peers.on('connection', async socket => {
 
         // rtpCapabilities is set for callback
         console.log('[getRtpCapabilities] callId', callId);
-        callbackResponse = videoCalls[callId].router.rtpCapabilities;
+        callbackResponse = { 
+          rtpCapabilities :videoCalls[callId].router.rtpCapabilities
+        };
+        callback(callbackResponse);
       } else {
         console.log(`[createRoom] missing callId ${callId}`);
       }