可能是因为Android 11中已经更改了网络连接权限的处理方式，因此导致Webrtc VOIP呼叫无法正常工作。为解决这个问题，可以尝试加入以下代码：

//在AndroidManifest.xml文件中添加以下权限请求

//在代码中使用以下代码配置Webrtc客户端

PeerConnectionFactory.initialize(PeerConnectionFactory.InitializationOptions.builder(this)

    .createInitializationOptions());

PeerConnectionFactory.Options options = new PeerConnectionFactory.Options();

DefaultVideoEncoderFactory defaultVideoEncoderFactory = new DefaultVideoEncoderFactory(

    rootEglBase.getEglBaseContext(), true /* enableIntelVp8Encoder */, true);

DefaultVideoDecoderFactory defaultVideoDecoderFactory = new DefaultVideoDecoderFactory(

    rootEglBase.getEglBaseContext());

PeerConnectionFactory peerConnectionFactory = PeerConnectionFactory.builder()

    .setOptions(options)

    .setVideoEncoderFactory(defaultVideoEncoderFactory)

    .setVideoDecoderFactory(defaultVideoDecoderFactory)

    .createPeerConnectionFactory();

//配置STUN和TURN服务器

List iceServers = new ArrayList<>();

iceServers.add(PeerConnection.IceServer.builder("stun:stun.l.google.com:19302").createIceServer());

iceServers.add(PeerConnection.IceServer.builder("turn:turn.example.org").setUsername("username").setPassword("password").createIceServer());

PeerConnectionFactory.Options rtcConfig = new PeerConnectionFactory.Options();

rtcConfig.setIceServerUrls(Collections.singletonList("stun:stun.l.google.com:19302"));

rtcConfig.setIceServers(iceServers);

PeerConnectionFactory.initialize(PeerConnectionFactory.InitializationOptions.builder(this).setPeerConnectionFactoryOptions(rtcConfig).createInitializationOptions());

//创建PeerConnection

PeerConnectionFactory.Options rtcConfig = new PeerConnectionFactory.Options();

rtcConfig.setIceServerUrls(Collections.singletonList("stun:stun.l.google