> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cognigy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Troubleshooting

This page covers common issues you may encounter when using the Cognigy Click To Call SDK and how to resolve them.

## Connection Issues

<AccordionGroup>
  <Accordion title="Client Fails to Connect">
    **Symptom**: Calling `connect()` or `connectAndCall()` throws an error or times out.

    **Possible Causes and Solutions**:

    * **Incorrect endpoint URL**. Verify that the `endpointUrl` in your configuration is correct and accessible. The URL must point to a valid Cognigy Click To Call configuration endpoint.
    * **Network restrictions**. Ensure that your network allows WebSocket connections and UDP traffic, both of which are required for SIP/WebRTC communication. Check firewall and proxy settings.
    * **CORS issues**. If the SDK can't fetch the SIP configuration, the endpoint server may not be configured to allow cross-origin requests from your domain.
  </Accordion>

  <Accordion title="SIP Registration Fails">
    **Symptom**: The `registered` event is never emitted, or the `error` event emits after connecting.

    **Possible Causes and Solutions**:

    * **Invalid SIP credentials**. The SIP configuration returned by the endpoint URL may contain invalid credentials. Contact your Cognigy administrator to verify the configuration.
    * **SIP server unreachable**. Ensure that the SIP server is reachable from the client's network. Network firewalls may block the required ports.
  </Accordion>
</AccordionGroup>

## Call Issues

<AccordionGroup>
  <Accordion title="Call Not Starting">
    **Symptom**: `startCall()` throws an error or doesn't initiate a call.

    **Possible Causes and Solutions**:

    * **Client not connected**. Ensure that `connect()` has been called and the `registered` event has been received before calling `startCall()`. Alternatively, use `connectAndCall()` to combine both steps.
    * **Microphone permission denied**. The browser requires microphone access for Click To Call calls. Ensure that the user has granted microphone permission.
  </Accordion>

  <Accordion title="No Audio">
    **Symptom**: The call connects, but no audio is heard.

    **Possible Causes and Solutions**:

    * **Autoplay policy**. Modern browsers block autoplay of media with audio. Ensure that the call is initiated by a user gesture, for example, a button click. The SDK manages audio playback internally via an `Audio` element, but browser autoplay restrictions still apply.

    * **ICE/TURN configuration**. If audio doesn't work, it may be a NAT traversal issue. Configure a TURN server in the `pcConfig` option:

      ```typescript theme={null}
      const client = await createWebRTCClient({
        endpointUrl: 'https://your-api.com/voice-connect-config',
        pcConfig: {
          iceServers: [
            { urls: 'stun:stun.l.google.com:19302' },
            {
              urls: 'turn:your-turn-server.com:3478',
              username: 'user',
              credential: 'password'
            }
          ]
        }
      });
      ```

    * **No audio tracks in stream**. The remote stream may not contain audio tracks. Check the browser developer console for warnings from the SDK such as "Stream has no audio tracks".
  </Accordion>

  <Accordion title="Call Drops Unexpectedly">
    **Symptom**: The [`ended`](/click-to-call/sdk/event-reference/ended) or [`failed`](/click-to-call/sdk/event-reference/failed) event emits shortly after the call starts.

    **Possible Causes and Solutions**:

    * **Network instability**. Check the network connection. Click To Call is sensitive to network changes, especially on mobile devices.
    * **Session timeout**. The SIP server may have a session timeout configuration. Check the `CallEndInfo` object in the `ended` or `failed` event callback for the `cause`, `originator`, and `description` fields.
  </Accordion>
</AccordionGroup>

## Transcription Issues

<AccordionGroup>
  <Accordion title="Transcription Events Not Received">
    **Symptom**: The [`transcription`](/click-to-call/sdk/event-reference/transcription) event is never emitted during a call.

    **Possible Causes and Solutions**:

    * **Transcription not enabled**. Ensure that transcription is enabled in your Voice Gateway or Cognigy Flow configuration.
    * **Info messages without `_transcription`**. Transcription events are only emitted when an incoming info message contains a `_transcription` property. Regular info messages are emitted via [`infoReceived`](/click-to-call/sdk/event-reference/info-received) instead.
  </Accordion>
</AccordionGroup>

## Browser Issues

<AccordionGroup>
  <Accordion title="Click To Call Not Supported">
    **Symptom**: [`checkWebRTCSupport()`](/click-to-call/sdk/api-reference/check-click-to-call-support) returns `{ supported: false }`.

    **Possible Causes and Solutions**:

    * **Unsupported browser**. The SDK requires a browser that supports WebRTC APIs: `RTCPeerConnection`, `getUserMedia`.
    * **Insecure context**. WebRTC APIs are only available in [secure contexts](https://developer.mozilla.org/en-US/docs/Web/Security/Secure_Contexts) such as HTTPS or `localhost`. Ensure your application is served over HTTPS.
  </Accordion>

  <Accordion title="Microphone Permission Issues">
    **Symptom**: The browser prompts for microphone access but the call fails.

    **Possible Causes and Solutions**:

    * **Permission denied**. The user must grant microphone permission. If denied, the browser won't allow access to the local audio stream.
    * **Permission previously blocked**. If the user previously blocked microphone access, they need to manually reset the permission in the browser's site settings.
  </Accordion>
</AccordionGroup>

## Error Handling

The SDK supports two complementary approaches for catching errors.

<AccordionGroup>
  <Accordion title="Promise-Based">
    All async methods return promises. Wrap them in the `try` and `catch` blocks:

    ```typescript theme={null}
    try {
      await client.connect();
      await client.startCall();
    } catch (error) {
      console.error('Operation failed:', error.message);
    }
    ```
  </Accordion>

  <Accordion title="Event-Based">
    Subscribe to the [`error`](/click-to-call/sdk/event-reference/error) event to catch asynchronous errors during the SDK lifecycle:

    ```typescript theme={null}
    client.on('error', (error) => {
      console.error('Click To Call SDK error:', error.message);
    });
    ```
  </Accordion>
</AccordionGroup>

<Tip>
  Combine both approaches. The `try` and `catch` blocks capture errors from direct calls, while the `error` event handles asynchronous errors.
</Tip>

## Debugging Tips

<AccordionGroup>
  <Accordion title="Enable Event Logging">
    Register listeners for all key events to trace the SDK lifecycle:

    ```typescript theme={null}
    client.on('connecting', () => console.log('[WebRTC] Connecting...'));
    client.on('connected', () => console.log('[WebRTC] Connected'));
    client.on('registered', () => console.log('[WebRTC] Registered'));
    client.on('disconnected', () => console.log('[WebRTC] Disconnected'));
    client.on('answered', (s) => console.log('[WebRTC] Answered:', s.id));
    client.on('ended', (s, info) => console.log('[WebRTC] Ended:', info));
    client.on('failed', (s, info) => console.error('[WebRTC] Failed:', info));
    client.on('error', (err) => console.error('[WebRTC] Error:', err.message));
    ```
  </Accordion>

  <Accordion title="Inspect WebRTC Internals">
    In Chrome, navigate to `chrome://webrtc-internals/` to view detailed information about active WebRTC connections, including ICE candidates, codec negotiation, and media statistics.
  </Accordion>

  <Accordion title="Check Network Traffic">
    Use the browser's DevTools **Network** tab to inspect WebSocket connections and verify that the SIP signaling messages are being exchanged correctly.
  </Accordion>
</AccordionGroup>