Invalid description, no ice-ufrag attribute at level 0 Error

I was trying to implement a sipjs session.

initializeSip() {
const uri = UserAgent.makeURI('sip:[email protected]'); // Replace with your SIP URI
if (!uri) {
  throw new Error('Failed to create URI');
}

const userAgentOptions: UserAgentOptions = {
  uri,
  transportOptions: {
    server: 'ws://127.0.0.1:9090',
  },

  delegate: {
    onInvite: (invitation: Invitation) => {
      return this.handleIncomingCall(invitation);
    },
  },
};

this.userAgent = new UserAgent(userAgentOptions);

const registererOptions: RegistererOptions = {
  // Customize registererOptions as needed
};
this.registerer = new Registerer(this.userAgent, registererOptions);

this.userAgent.start().then(() => {
  this.registerer.register();
})}

this is how defined accept call in handleIncomingCall function

const acceptCall = () => {
  const constraints = {
    audio: true,
    video: false,
  };

  navigator.mediaDevices
    .getUserMedia(constraints)
    .then((localStream) => {
      // Attach local stream to an audio element if needed
      const localAudio = document.getElementById(
        'localAudio'
      ) as HTMLAudioElement;
      if (localAudio) {
        localAudio.srcObject = localStream;
      }
    })
    .catch((error) => {
      console.error('Error getting user media:', error);
    });

  const peerConnectionConfig = {
    iceServers: [
      {
        urls: ['stun:stun.l.google.com:19302'],
        
      },
    ],
    iceTransportPolicy: 'all',
    bundlePolicy: 'balanced' as RTCBundlePolicy,
    rtcpMuxPolicy: 'require' as RTCRtcpMuxPolicy,
  };

  const options = {
    sessionDescriptionHandlerOptions: {
      constraints,
      peerConnectionConfiguration: peerConnectionConfig,
      peerConnectionOptions: {
        rtcConfiguration: peerConnectionConfig,
        iceGatheringTimeout: 5000,
      },
    },
  };

  // Accept the call
  // Adding the listener for state changes

  invitation
    .accept(options)
    .then(() => {
      console.log('Call accepted successfully');
    })
    .catch((error) => {
      console.error('Failed to accept call:', error);
    });
};

I configured discription and pass that to an argument while accepting the invitation. but even after i am passing i an getting below error. i tried to solve in many ways, but nothing seems working.is there any mistakes while i passing the ice flags ?

sip.SessionDescriptionHandler | SessionDescriptionHandler.setDescription failed – InvalidAccessError: Invalid description, no ice-ufrag attribute at level 0