11200: HTTP retrieval failure

Twilio was unable to retrieve a successful response from your webhook URL. This error means Twilio sent an HTTP request to the URL you configured (for example, a TwiML endpoint or a status callback) and received either a non-2xx response, a connection failure, or a response it could not parse. When possible, Twilio raises a more specific error code. Error 11200 appears when the exact cause does not match a narrower code.

• Your web server returned a 4xx or 5xx HTTP status code to Twilio.
• A network disruption between Twilio and your server prevented the connection from completing. This can occur within your infrastructure, within Twilio, or anywhere on the public internet.
• A firewall, WAF, or rate limiter blocked the inbound request from Twilio. WAF rules that apply to only a subset of requests can cause intermittent failures.
• The webhook URL redirects (302) to an invalid or unreachable destination.
• The URL is protected by HTTP authentication that Twilio cannot satisfy.
• Your server does not accept HTTP POST requests for the resource (for example, a static .xml or .html file served by a server that only allows GET).
• The URL host resolves to a private or localhost IP address that Twilio cannot reach.
• No Content-Type header is included in the response, or the Content-Type does not match the actual content (for example, serving an MP3 file with Content-Type: audio/x-wav instead of Content-Type: audio/mpeg).
• Your server takes too long to respond, causing the request to time out before Twilio receives a complete response.
• You applied webhook connection overrides that reduced the timeout or changed connection behavior in a way that conflicts with your server's response time.

• Confirm your webhook URL returns a 2xx status code. Send a test request from your own machine or a monitoring tool to verify.
• Check your server logs at the network edge to determine whether Twilio's request arrived. If TCP connections from Twilio are not reaching your infrastructure, review firewall, WAF, and load balancer rules that may block or rate-limit requests from Twilio. See Webhooks and IP addresses for details on Twilio's cloud architecture.
• If your URL performs a redirect, verify the redirect target is a valid, publicly reachable URL that also returns a 2xx response.
• Remove HTTP authentication from the webhook endpoint, or use webhook signature validation to verify requests instead.
• Ensure your web server allows HTTP POST requests to the webhook path. If you serve static TwiML files, configure the server to respond to both GET and POST.
• Verify the URL host resolves to a public IP address. Twilio cannot reach 127.0.0.1, 10.x.x.x, 192.168.x.x, or other private ranges.
• Measure response time from your server. If processing takes more than a few seconds, respond immediately with an empty 200 OK or 204 No Content and process the event asynchronously. For inbound messages, you can reply at any time by calling the REST API.
• Remove any webhook connection overrides to restore default timeout and connection behavior, then test again.
• Verify the response includes a Content-Type header that matches the actual body content.
• Set a fallback URL on your Twilio phone number or TwiML app, ideally hosted on separate infrastructure, so Twilio can retry on a different endpoint if your primary URL fails.
• If the error is intermittent and you have confirmed the requests are reaching your server correctly, collect the timestamps and request SIDs and open a support ticket.

• Webhook security
• Debugging tools
• Event Streams