The signature for the Access Token provided was invalid.
Check that your code is correctly generating signatures using the algorithm and format expected by the Twilio API.
To check whether the Access Token is structurally correct, you can use the tools available at jwt.io.
Access Tokens are used by multiple Twilio SDKs, including Programmable Voice, Programmable Video, and Programmable Chat. For the details of Twilio's specific Access Token implementation, see the documentation.