Troubleshooting Twilio Elastic SIP Trunking and SIP Domain Calls

This guide is intended to help troubleshoot any issues with Twilio Elastic SIP Trunking, and SIP Domain voice calls. This guide covers the following topics for diagnosing and resolving your issues:

Please start at the top, and walk through each of the troubleshooting steps as you work your way down the page.

Check Your Call Logs

Check the Twilio Call Logs to validate that we have successfully received and processed a request for a call. You can view the logs and search for your call record via either Console, or the REST API.

A record does exist for the call, but the call doesn't connect: If you do see a record for the call in question, but the call destination isn't connected, then there is likely an issue elsewhere. Continue reading for additional troubleshooting.

A record does exist for the call: If you do see a record for the call in question, this indicates Twilio has successfully received the a request for a call, and the issue lies elsewhere. Continue troubleshooting with the following checklist:

A record doesn't exist for the call: If you don't see a record for the call in question, this indicates Twilio did not receive a request for this call.

Check the Packet Captures (PCAPs)

If a call doesn't connect, check your packet captures to see the SIP response code. This code should give you a clue as to why the call was not connected. Pcap files for Twilio SIP calls are found in the Console Call Logs. For an overview, please see View Twilio SIP Call Packet Captures (PCAPs).

Check for Twilio Incidents

Check the Twilio Status Page to see if there is an active incident, or an incident during the timeframe you reported issues, that could be causing your issues. For full details, please see Checking Twilio Service and API Status with the Status Page.

No incidents are listed that may be affecting calls: If you don't see an incident posted that may affect calls, then there is likely an issue elsewhere. Continue reading for additional troubleshooting.

An incident may be affecting calls: If you see an incident posted that may affect outgoing Twilio calls, please monitor the status, and then test again once the incident is resolved.

Test and Collect Information

If there are no known Twilio issues, we will need to perform additional testing to determine issue reproducibility, variance, and frequency:

  • Does you have issues connecting all calls, or just to specific phone numbers?
  • Does this occur all the time to the same numbers, or does it seem more random?

All calls have trouble connecting: If none of your Twilio calls are able to successfully connect to any phone number, then there may have been an issue missed previously. Review the previous troubleshooting, and then continue reading if you are unable to determine the source of your problems.

Some phone numbers have trouble connecting: If you are able to place some successful calls, but specific phone numbers have issues with connecting successfully, then there is likely an issue elsewhere. Notate your testing results, and then continue reading for additional troubleshooting.

Connection issues are inconsistent: If you are unable to determine a pattern with connection issues, we will likely need to look into this closer. What are the commonalities between examples (service providers, locations, etc.)? Notate your testing results, and then continue reading for additional troubleshooting.

Escalate to Twilio Support

If you can rule out all of the above issues, Twilio's Support team can help investigate what went wrong. Please collect 3 or more examples of calls that are not registering in your call log from the last 24 hours, and include the following information:

  • Caller (from) number
  • Callee (to) number
  • Your Twilio project Account SID
  • Call SIDs
  • Timestamps of call attempts
  • Description of issue reported
  • Reproducibility and frequency of issue

When you have collected this information, please share it with our Support team.

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