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Error - 11200

HTTP retrieval failure

There was a failure attempting to retrieve the contents of this URL.

An 11200 error is an indicator of a connection failure between Twilio and your service. When Twilio requests a page from your server, we wait a maximum of 15 seconds for a response. A connection failure will occur if no response is returned in that time.

There are many reasons a connection timeout can occur; common causes are long running database queries or outside processes and calls to external systems taking a long time to return. It may be possible your application experienced one of these issues. If you are encountering this error only intermittently, it is possible that your web server was temporarily unavailable or experiencing a network outage.

502 Bad Gateway errors

If your debugger is reporting a 502 Bad Gateway error, this may mean that Twilio's internal server had trouble retrieving content from your website. Your request must contain a Content-Type that is valid. Twilio may also have had problems resolving your DNS name to an IP address, or issues with the network connection. Check that your web server is started, and is available over the public Internet.

Possible Causes

  • Web server returned a 4xx or 5xx HTTP response to Twilio
  • Misconfigured Web Server
  • Network disruptions between Twilio and your web server
  • No Content-Type header attached to response
  • Content-Type doesn't match actual content, e.g. an MP3 file that is being served with Content-Type: audio/x-wav, instead of Content-Type: audio/mpeg

Possible Solutions

  • Double check that your TwiML URL does not return a 4xx or 5xx error
  • Make certain that the URL does not perform a 302 redirect to an invalid URL
  • Confirm the URL requested is not protected by HTTP Auth
  • Make sure your web server allows HTTP POST requests to static resources (if the URL refers to .xml or .html files)
  • Verify your web server is up and responsive
  • Check to see that the URL host is not a private or local IP address
  • Verify the ping times and packet loss between your web server and www.twilio.com