If you experience an issue where your call failed to go through or behaved unexpectedly, the Request Inspector may be able to help. This tool is located in your call logs and provides information on the requests Twilio makes to your application and the response Twilio receives. Twilio keeps these logs for 90 days. Here’s how to access the Request Inspector:

1. Login to your Twilio project

2. Access your call logs and identify the call where the problem occurred. Click the hyperlinked date to access details on this call.

3. The Request Inspector displays all requests and responses made during this call. You can easily locate the request which encountered an error by the color coded statuses on the left. Click the request to expand the information.

4. Twilio made a request to /action.xml but received an HTTP 404 back from the web server. Since Twilio did not receive any new TwiML to execute, the call terminated.

5. To continue troubleshooting, we should look into why our web server is responding to HTTP requests from Twilio with HTTP 404.