13807: Client Notification URL Error Response

Twilio returns this error when the clientNotificationUrl used for a Voice SDK client call notification responds with an error instead of a successful webhook response. Twilio uses this URL to deliver a POST request for the Client Call Notification Webhook when you route a call to a Voice SDK client.

• Your webhook returned a 5xx response because the application handling the Client Notification URL request failed.
• Your webhook returned 400, 401, or 403 because the endpoint rejected the request due to request validation, authentication, authorization, or another server-side configuration issue. Twilio sends this webhook as an HTTP POST with a JSON body.
• Your clientNotificationUrl points to the wrong endpoint. This commonly results in a 404 Not Found response.
• Your application returned 404 Not Found because it could not find a client binding that matched the target identity and Twilio Account SID.
• Your clientNotificationUrl is not configured with a valid hostname or includes an underscore in the hostname. For <Client> TwiML, this parameter only accepts POST.

• Verify that clientNotificationUrl is set to the correct publicly reachable webhook endpoint in your Calls API request or <Client> TwiML.
• Update your webhook handler to accept an HTTP POST request with a JSON body and return 200 OK after you successfully dispatch the notification to the target client.
• If no matching client binding exists, create or refresh the binding before routing calls to that identity. If the user is no longer registered, stop routing calls to that user until a valid binding is available.
• Review any authentication, authorization, or request-validation logic on the endpoint so the webhook request can be processed successfully instead of returning 400, 401, or 403.
• If you handle your own mobile push delivery, pass the notification payload your application receives to Voice.handleMessage() on Android or TwilioVoiceSDK.handleNotification() on iOS after your application delivers it to the client.

• Client Call Notification Webhook
• TwiML Voice <Client>
• Call resource