Error Codes - Twilio
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Error Codes

All Programmable Voice Error Codes are five-digit integers. Below is the list of errors Programmable Voice is currently using. Note that we are still working on finalizing the list and it may change while in Beta.

General Errors

Code Description Explanation
31000 Generic error. A call error occurred that is not covered by a more specific error code. No further information available. Check the debugger for more info.
31003 Connection timeout. The server could not produce a response within a suitable amount of time.
31004 Initialization error in iOS SDK. The iOS SDK couldn't initialize user agent due to an internal error.
31005 Connection error. A connection error occurred during the call.
31006 Audio device error. Unable to start the audio device.

Malformed Requests

Code Description Explanation
21218 TwiML application not found. The server was not able to find the TwiML application associated with the App SID.
31100 Malformed request. The request could not be understood due to malformed syntax.
31106 Invalid data. The provided data to handleMessage(...)/handleNotification(...) API was not valid.
31107 No CallInvite with this CallSid. A cancel notification was received for a non existing CallInvite.

Authorization Errors

Code Description Explanation
20101 Invalid access token. The Access Token provided to the SDK is invalid. This may happen when the Access Token is structurally incorrect.
20102 Invalid Access Token header. The header of the Access Token provided to the SDK is invalid.
20103 Invalid Access Token issuer/subject. The issuer or subject of the Access Token provided is invalid.
20104 Access Token expired or expiration date invalid. The Access Token provided to the SDK has expired, the expiration time specified in the token was invalid, or the expiration time specified was too far in the future.
20105 Access Token not yet valid. The Access Token provided to the SDK is not yet valid.
20106 Invalid Access Token grants. The Access Token does not include voice grants.
20107 Invalid Access Token signature. The signature for the Access Token provided was invalid. Ensure the secret included in the Access Token is valid.
20151 The authorization with Token failed. The system could not perform the authorization for the given request.
20157 Expiration Time Exceeds Maximum Time Allowed. The expiration time provided in the Access Token exceeds the maximum duration allowed.
20403 403 Forbidden. The expiration time provided in the Access Token exceeds the maximum duration allowed.
31201 Authorization error. The server understood the request, but is refusing to fulfill it. This happens when a CallInvite is generated from invalid data.

Registration Errors

Code Description Explanation
31301 Registration or Unregistration failed. The registration request to Twilio failed with an exception. This can be caused by an http related error or by an invalid push credential.

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