The Access Token provided to the Twilio API has expired, the expiration time specified in the token was invalid, or the expiration time specified was too far in the future.
Access Token expiration times can be set up to 24 hours in the future.
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.