Can't SurfaceViewRenderer: local_gl_surface_view on android

I am developing a video call system includes an android app.
Its sometimes doesn’t render the enemy camera. When I change PeerConnection.IceServer, it has improved slightly.

  • If the fuction onIceConnectionChange be invoked and iceConnectionState is “Connected” two times, Android app will render the enemy camera’s frame normaly. But if just one time “Connected” be notified, just displays only black screen. even though the enemy device is still displaying full information.
    → The IceServer has problem or my android app has problem?