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Troubleshooting Incoming Calls on a Twilio Phone Number

This guide is intended to help troubleshoot any issues with receiving incoming calls on a Twilio-supplied phone number. 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 the incoming call(s). You can view the logs and search for your call record via either Console, or the REST API.

A record doesn't exist for the call: If you don't see a record for the call in question, 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 call, and the issue lies elsewhere. Continue troubleshooting with the following checklist:

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 incoming calls to your Twilio phone number, please monitor the status, and then test again once the incident is resolved.

Check Phone Number Configuration

Check the Incoming Phone Numbers on your Twilio project to verify your phone number is correctly configured to receive calls. You can see your phone number's configuration via either the Active Numbers page in Console or the REST API.

Here's what a properly configured phone number should look like:

  • Console: A phone number configured to receive incoming calls must say Voice under CONFIGURATION on the Active Numbers page in Console. Additionally, the phone number must have a supported method for receiving calls.
  • REST API: A phone number configured to receive incoming calls must have the voice_receive_mode value voice, and then one of the following:
    • A valid voice_url
    • A valid voice_application_sid
    • A valid trunk_sid

The phone number is configured correctly: If your Twilio phone number has a valid known working configuration, then there is likely an issue elsewhere. Continue reading for additional troubleshooting.

The phone number is not configured correctly: If your Twilio phone number is not configured correctly, you'll need to update this before you're able to successfully receive voice calls. For help updating your phone number's configuration, please see Configuring Phone Numbers to Receive Voice Calls.

  • If Fax is listed in Console under CONFIGURATION, or returned by the REST API as the voice_receive_mode value, this indicates your number is configured to receive all incoming calls as faxes. In this state, incoming calls are not tracked in your Twilio project, and attempted callers will likely hear a fast busy signal or analog modem handshake sounds. Twilio numbers are unable to be configured for simultaneous incoming faxes and voice calls; we only support one of these options at a time.
  • If your number is configured voice voice calls, but displays Unconfigured in Console under CONFIGURATION, or the REST API returns empty values for voice_url, voice_application_sid, and trunk_sid, this indicates your number is not configured to answer calls. In this state, incoming calls are not tracked in your Twilio project, and attempted callers will likely hear a standard error message (Example: "The number you have called can not be reached. Please hang up and try your call again.").

Test and Collect Information

If there are no known Twilio issues, and your phone number is configured correctly, we will need to perform additional testing to determine issue reproducibility, variance, and frequency:

  • Are you able to reproduce the same issues reported under the same conditions?
  • Does the issue show up in the same manner on all reports?
  • What percentage of calls have reported issues?

All callers always share the same experience: If all incoming calls to your Twilio phone number from different sources (landline, wireless, VoIP, other providers) are unable to successfully connect, then there is likely an issue elsewhere. Continue reading for additional troubleshooting.

All callers sometimes share the same experience: If all incoming callers to your Twilio phone number from different sources have reported inconsistent issues with connecting successfully, then there is likely an issue elsewhere. Notate their testing results, and then continue reading for additional troubleshooting.

Different callers have different experiences: If different callers report different experiences when calling your Twilio phone number, then there may be an issue from the caller's side. What are the commonalities between examples (service providers, locations, etc.)?

  • If non-connecting examples are from only one particular service provider or location, while numbers from other service providers are able to connect successfully, escalate examples of non-connecting calls to the service provider that is unable to connect.

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
  • Your Twilio phone number
  • From number service provider
  • Your Twilio project Account SID
  • Call SIDs (If you have them)
  • 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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