Many errors using flutter_webrtc

Question

I am trying to implement video and voice call app using flutter_webrtc and this is my function which I have an error when I trying to call its successful only first time and the second time I got an exception: peerConnectionSetRemoteDescription(): WEBRTC_SET_REMOTE_DESCRIPTION_ERROR: Failed to set remote answer sdp: Called in wrong state: stable , closed

Future setupPeerConnection() async {
    _rtcPeerConnection = await createPeerConnection({
      'sdpSemantics': 'plan-b',
      'iceServers': [
        {
          'urls': [
            'stun:stun1.l.google.com:19302',
            'stun:stun2.l.google.com:19302'
          ]
        }
      ]
    });

    _localStream = await navigator.mediaDevices.getUserMedia({
      'audio': isAudioOn,
      'video': isVideoOn
          ? {'facingMode': isFrontCameraSelected ? 'user' : 'environment'}
          : false,
    });

    _localStream!.getTracks().forEach((track) {
      _rtcPeerConnection!.addTrack(track, _localStream!);
    });

    _localRTCVideoRenderer.srcObject = _localStream;

    _rtcPeerConnection!.onTrack = (event) {
      _remoteRTCVideoRenderer.srcObject = event.streams[0];
    };
    update();

    // for Incoming call
    if (offer != null) {
      socket!.on("IceCandidate", (data) {
        String candidate = data["iceCandidate"]["candidate"];
        String sdpMid = data["iceCandidate"]["id"];
        int sdpMLineIndex = data["iceCandidate"]["label"];
        _rtcPeerConnection!.addCandidate(RTCIceCandidate(
          candidate,
          sdpMid,
          sdpMLineIndex,
        ));
      });
      final remoteDescription =
          RTCSessionDescription(offer["sdp"], offer["type"]);

      await _rtcPeerConnection!.setRemoteDescription(remoteDescription);

      RTCSessionDescription answer = await _rtcPeerConnection!.createAnswer();

      await _rtcPeerConnection!.setLocalDescription(answer);

      log(_rtcPeerConnection!.signalingState.toString());

      socket!.emit("answerCall", {
        "sender": sender,
        "sdpAnswer": answer.toMap(),
      });
    }
    // for Outgoing call
    else {
      _rtcPeerConnection!.onIceCandidate =
          (RTCIceCandidate candidate) => rtcIceCandidates.add(candidate);

      RTCSessionDescription offer = await _rtcPeerConnection!.createOffer();

      await _rtcPeerConnection!.setLocalDescription(offer);

      socket!.emit('makeCall', {
        "receiver": receiver,
        "sdpOffer": offer.toMap(),
        "isVoice": isVoiceCall
      });

      socket!.on("callAnswered", (data) {
        _rtcPeerConnection!.setRemoteDescription(
          RTCSessionDescription(
            data["sdpAnswer"]["sdp"],
            data["sdpAnswer"]["type"],
          ),
        );

        for (RTCIceCandidate candidate in rtcIceCandidates) {
          socket!.emit("IceCandidate", {
            "receiver": receiver,
            "iceCandidate": {
              "id": candidate.sdpMid,
              "label": candidate.sdpMLineIndex,
              "candidate": candidate.candidate
            }
          });
        }
      });
    }
  }

and this how I dispose the controller:

Future disposeConnection() async {
    _localStream?.getVideoTracks().forEach((track) async {
      await track.stop();
    });
    _localStream?.getAudioTracks().forEach((track) async {
      await track.stop();
    });

    await _localStream?.dispose();
    await _rtcPeerConnection!.close();
    // await _localRTCVideoRenderer.dispose();
    // await _remoteRTCVideoRenderer.dispose();
  }

I have been stacked here for more than week can anyone help me!!

edit!! here is my full controller:

import 'dart:developer';

import 'package:flutter/material.dart';
import 'package:get/get.dart' hide navigator;
import 'package:sizer/sizer.dart';

import '../socket/socket_controller.dart';
import 'package:flutter_webrtc/flutter_webrtc.dart';

class VideoCallController extends GetxController {
  final socket = Get.find<SocketController>().socket;
  final String sender, receiver;
  dynamic offer;
  bool isVoiceCall;
  bool isSender;

  final _localRTCVideoRenderer = RTCVideoRenderer();
  final _remoteRTCVideoRenderer = RTCVideoRenderer();

  get localRTCVideoRenderer => _localRTCVideoRenderer;
  get remoteRTCVideoRenderer => _remoteRTCVideoRenderer;
  MediaStream? _localStream;
  RTCPeerConnection? _rtcPeerConnection;
  List<RTCIceCandidate> rtcIceCandidates = [];

  bool isAudioOn = true,
      isVideoOn = true,
      isFrontCameraSelected = true,
      isTopSpeakerSelected = true;

  Offset myOffset = Offset(MediaQuery.sizeOf(Get.context!).width * 0.55, 50);
  final double myContainerWidth = 40.w;
  final double myContainerHeight = 25.h;

  Offset thereOffset = Offset(MediaQuery.sizeOf(Get.context!).width * 0.55, 50);
  final double thereContainerWidth = 40.w;
  final double thereContainerHeight = 25.h;

  bool myViewIsMain = false;

  VideoCallController(
      {this.offer,
      required this.isVoiceCall,
      required this.isSender,
      required this.sender,
      required this.receiver});

  @override
  void onInit() async {
    await _localRTCVideoRenderer.initialize();
    await _remoteRTCVideoRenderer.initialize();
    if (isVoiceCall) {
      isVideoOn = false;
      isTopSpeakerSelected = false;
      update();
    }
    setupPeerConnection();
    handleRemoteExitCall();
    handleRemoteCancelCall();
    super.onInit();
  }

  @override
  void onClose() async {
    await disposeConnection();
    super.onClose();
  }

  Future disposeConnection() async {
    _localStream?.getVideoTracks().forEach((track) async {
      await track.stop();
    });
    _localStream?.getAudioTracks().forEach((track) async {
      await track.stop();
    });
    await _localStream?.dispose();
    await _rtcPeerConnection!.close();

    // await _localRTCVideoRenderer.dispose();
    // await _remoteRTCVideoRenderer.dispose();
  }

  switchView() {
    myViewIsMain = !myViewIsMain;
    myOffset = Offset(MediaQuery.sizeOf(Get.context!).width * 0.55, 50);
    thereOffset = Offset(MediaQuery.sizeOf(Get.context!).width * 0.55, 50);
    update();
  }

  void myOverlayPosition(DragUpdateDetails d) {
    double newOffsetX = myOffset.dx + d.delta.dx;
    double newOffsetY = myOffset.dy + d.delta.dy;
    Size screenSize = MediaQuery.of(Get.context!).size;
    double maxOffsetX = screenSize.width - myContainerWidth;
    double maxOffsetY = screenSize.height - myContainerHeight;
    double topRange = 4.h;
    double bottomRange = 13.h;
    maxOffsetY -= topRange + bottomRange;
    newOffsetX = newOffsetX.clamp(0, maxOffsetX);
    newOffsetY = newOffsetY.clamp(topRange, maxOffsetY + topRange);
    myOffset = Offset(newOffsetX, newOffsetY);
    update();
  }

  void thereOverlayPosition(DragUpdateDetails d) {
    double newOffsetX = thereOffset.dx + d.delta.dx;
    double newOffsetY = thereOffset.dy + d.delta.dy;
    Size screenSize = MediaQuery.of(Get.context!).size;
    double maxOffsetX = screenSize.width - thereContainerWidth;
    double maxOffsetY = screenSize.height - thereContainerHeight;
    double topRange = 4.h;
    double bottomRange = 13.h;
    maxOffsetY -= topRange + bottomRange;
    newOffsetX = newOffsetX.clamp(0, maxOffsetX);
    newOffsetY = newOffsetY.clamp(topRange, maxOffsetY + topRange);
    thereOffset = Offset(newOffsetX, newOffsetY);
    update();
  }

  setupPeerConnection() async {
    _rtcPeerConnection = await createPeerConnection({
      'iceServers': [
        {
          'urls': [
            'stun:stun1.l.google.com:19302',
            'stun:stun2.l.google.com:19302'
          ]
        }
      ]
    });

    _localStream = await navigator.mediaDevices.getUserMedia({
      'audio': isAudioOn,
      'video': isVideoOn
          ? {'facingMode': isFrontCameraSelected ? 'user' : 'environment'}
          : false,
    });

    _localStream!.getTracks().forEach((track) {
      _rtcPeerConnection!.addTrack(track, _localStream!);
    });

    _localRTCVideoRenderer.srcObject = _localStream;

    _rtcPeerConnection!.onTrack = (event) {
      _remoteRTCVideoRenderer.srcObject = event.streams[0];
    };

    log(_rtcPeerConnection!.signalingState.toString());

    update();

    // for Incoming call
    if (offer != null) {
      final remoteDescription =
          RTCSessionDescription(offer["sdp"], offer["type"]);

      await _rtcPeerConnection!.setRemoteDescription(remoteDescription);

      RTCSessionDescription answer = await _rtcPeerConnection!.createAnswer();

      await _rtcPeerConnection!
          .setLocalDescription(answer)
          .then((value) => socket!.on("IceCandidate", (data) {
                String candidate = data["iceCandidate"]["candidate"];
                String sdpMid = data["iceCandidate"]["id"];
                int sdpMLineIndex = data["iceCandidate"]["label"];
                _rtcPeerConnection!.addCandidate(RTCIceCandidate(
                  candidate,
                  sdpMid,
                  sdpMLineIndex,
                ));
              }));

      socket!.emit("answerCall", {
        "sender": sender,
        "sdpAnswer": answer.toMap(),
      });
    }
    // for Outgoing call
    else {
      _rtcPeerConnection!.onIceCandidate =
          (RTCIceCandidate candidate) => rtcIceCandidates.add(candidate);

      RTCSessionDescription offer = await _rtcPeerConnection!.createOffer();

      await _rtcPeerConnection!.setLocalDescription(offer);

      socket!.emit('makeCall', {
        "receiver": receiver,
        "sdpOffer": offer.toMap(),
        "isVoice": isVoiceCall
      });

      socket!.on("callAnswered", (data) {
        _rtcPeerConnection!.setRemoteDescription(
          RTCSessionDescription(
            data["sdpAnswer"]["sdp"],
            data["sdpAnswer"]["type"],
          ),
        );

        for (RTCIceCandidate candidate in rtcIceCandidates) {
          socket!.emit("IceCandidate", {
            "receiver": receiver,
            "iceCandidate": {
              "id": candidate.sdpMid,
              "label": candidate.sdpMLineIndex,
              "candidate": candidate.candidate
            }
          });
        }
      });
    }
  }

  handleExitCall() {
    socket!.emit("userExitCall", {
      'exitUser': receiver,
    });
    Get.back();
  }

  handleRemoteExitCall() {
    socket!.on("isExitCall", (data) {
      Get.back();
    });
  }

  handleRemoteCancelCall() {
    socket!.on("isCancelCall", (data) async {
      Get.back();
    });
  }

  toggleMic() {
    isAudioOn = !isAudioOn;
    _localStream?.getAudioTracks().forEach((track) {
      track.enabled = isAudioOn;
    });
    update();
  }

  toggleCamera() {
    isVideoOn = !isVideoOn;
    _localStream?.getVideoTracks().forEach((track) {
      track.enabled = isVideoOn;
    });
    update();
  }

  switchCamera() {
    isFrontCameraSelected = !isFrontCameraSelected;
    _localStream?.getVideoTracks().forEach((track) {
      Helper.switchCamera(track);
    });
    update();
  }

  switchSpeaker() {
    isTopSpeakerSelected = !isTopSpeakerSelected;
    _localStream?.getAudioTracks().forEach((track) {
      track.enableSpeakerphone(isTopSpeakerSelected);
    });
    update();
  }
}