---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/80908#article
headline: "80908: Callback Error"
url: https://www.twilio.com/docs/api/errors/80908
inLanguage: en
dateModified: 2026-06-08T12:04:59.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 80908: Callback Error

Log Level: WARNING

## Description

This warning indicates that a request to the `callbackUrl` configured on your Proxy Service failed. Proxy uses `callbackUrl` to send informational webhooks for new interactions and interaction status changes.

### Possible causes

* The `callbackUrl` on your Proxy Service is invalid, points to the wrong route, or is no longer reachable from the public internet.
* Your endpoint does not handle Proxy webhook requests as `application/x-www-form-urlencoded` data, or it does not return HTTP `200 OK` for this informational webhook.
* Your endpoint returns a `4xx` or `5xx` response, times out, or fails during connection or TLS handshake setup.

### Possible solutions

* Verify that the Proxy Service `callbackUrl` is correct, publicly accessible, and updated to the exact route that should receive interaction callbacks.
* Update your webhook handler to accept Proxy form parameters and return HTTP `200 OK` after you process the callback.
* Open the URL directly in a browser or send a mock request to confirm that the route does not fail or redirect unexpectedly.
* Check the Debugger or Twilio Workbench to review the logged warning and inspect the HTTP request and response for the callback attempt.
* If intermittent network issues are causing failures, add webhook connection overrides to adjust timeout and retry behavior for the callback URL.

#### Additional resources

* [Proxy webhooks](/docs/proxy/api/webhooks)
* [Proxy Service resource](/docs/proxy/api/service)
* [Debugging your application](/docs/usage/troubleshooting/debugging-your-application)