I’m using pusher for the real time communication expecifically the messaging. but i’m getting this error

This is my implementation of init method.

  Future<void> initPusher(String roomID) async {
    _pusher = PusherChannelsFlutter.getInstance();
    try {
      await _pusher.init(
        apiKey: pusherKey,
        cluster: cluster,
        logToConsole: true,
        useTLS: true,
        onConnectionStateChange: onConnectionStateChange,
        onError: onError,
        onSubscriptionSucceeded: onSubscriptionSucceeded,
        onEvent: onEvent,
        onSubscriptionError: onSubscriptionError,
        onDecryptionFailure: onDecryptionFailure,
        onMemberAdded: onMemberAdded,
        onMemberRemoved: onMemberRemoved,
        authEndpoint: "${CmApiEndpoints.baseUrl}/broadcasting/auth",
        onAuthorizer: onAuthorizer,
      );
      //"presence-ChatRoom.$roomID"
      await _pusher.subscribe(channelName: "ChatRoom.$roomID");
      await _pusher.connect();
    } catch (e) {
      print("error in initialization: $e");
    }
  }

and the auth method

  dynamic onAuthorizer(
      String channelName, String socketId, dynamic options) async {
    String token = userToken;
    var authUrl = "${CmApiEndpoints.baseUrl}/broadcasting/auth";

    var result = await dioClient().post(
      authUrl,
      data: 'socket_id=$socketId&channel_name=$channelName',
      options: Options(
        headers: {
          'Content-Type': 'application/x-www-form-urlencoded',
          'Authorization': 'Bearer $token',
        },
      ),
    );
    var json = jsonDecode(result.data);
    return json;
  }