Fatal error，How to solve

[fgodlike]

When I run a compiled Apk on my Android phone, it's wrong

11-29 19:10:53.988 11589-11589/org.appspot.apprtc E/AppRTCMobileActivity: Fatal error: Attempt to invoke virtual method 'org.webrtc.DataChannel org.webrtc.PeerConnection.createDataChannel(java.lang.String, org.webrtc.DataChannel$Init)' on a null object reference

                                                                  java.lang.NullPointerException: Attempt to invoke virtual method 'org.webrtc.DataChannel org.webrtc.PeerConnection.createDataChannel(java.lang.String, org.webrtc.DataChannel$Init)' on a null object reference
                                                                      at org.appspot.apprtc.PeerConnectionClient.createPeerConnectionInternal(PeerConnectionClient.java:647)
                                                                      at org.appspot.apprtc.PeerConnectionClient.access$500(PeerConnectionClient.java:78)
                                                                      at org.appspot.apprtc.PeerConnectionClient$2.run(PeerConnectionClient.java:363)
                                                                      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
                                                                      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
                                                                      at java.lang.Thread.run(Thread.java:833)