31104: Invalid bridge token.

Twilio lists 31104 as "Invalid bridge token" within the Voice SDK error space and groups 311xx codes under malformed requests, indicating the client sent a malformed request that included an invalid bridge token.

• The Voice SDK request contained an invalid bridge token and was rejected as a malformed request
• Twilio classifies 311xx as malformed requests and defines 31104 as "Invalid bridge token."

• Generate a fresh Access Token for the client and retry, since Access Tokens authenticate Voice SDK clients and Twilio recommends checking them first when SDK errors occur
• Verify the Access Token's contents and grants are valid for your account and use case, and ensure the token has not expired
• Capture SDK error details and client logs, and review Twilio Debugger error logs to pinpoint malformed parameters before retrying
• If the issue persists after the above checks, contact Twilio Support with recent Call SIDs and debug logs for investigation

These steps reflect Twilio guidance to check AccessTokens first for Voice SDK errors, the short‑lived nature and validation of Access Tokens, the SDK's emitted error detail, and use of Debugger logs.

• Voice SDKs
• Debugging Your Twilio Application
• Common Twilio Programmable Voice SDK Error Codes and Debugging Help