51004: Client Connection: endpoint_id too long

Twilio rejected the client connection because the endpoint_id in the Access Token is longer than the supported maximum length. Reduce the length of the endpoint_id value and generate a new token before connecting the client.

• Your application generates an Access Token with an endpoint_id value that exceeds the allowed length.
• Your endpoint_id includes extra prefixes, identifiers, or concatenated values that make the final string too long.
• Your application builds the endpoint_id dynamically and does not validate its length before creating the token.

• Shorten the endpoint_id value in the Access Token and try the connection again.
• Update your token generation logic to validate the endpoint_id length before issuing the token.
• Remove unnecessary dynamic data from the endpoint_id, such as long environment names, session values, or repeated prefixes.
• Review your Voice SDK token generation flow to make sure the client identity and connection parameters stay within supported limits.

• Voice SDKs overview
• Access Tokens
• Programmable Voice documentation