51215: Twilsock: Unauthorized

This error means Twilsock rejected the client connection because it could not authorize the Access Token you supplied. Use short-lived Access Tokens to authenticate client-side SDKs. If authorization fails, the token is usually missing, invalid, expired, or issued with the wrong credentials or grants.

• Your application generated the token with the wrong Account SID, API Key SID, or API Secret, or mixed credentials from a different account or subaccount. (help.twilio.com)
• The token is expired, not yet valid, or your client continued using it after its lifetime ended. Access Tokens are short-lived and can be configured for up to 24 hours.
• The token does not include the correct grant or identity for the SDK you are initializing. Conversations and Sync both require you to issue the token on your server with the appropriate user identity and product grant.
• Your client passed the Access Token in the wrong format, such as a JSON object instead of the token string itself. (help.twilio.com)
• In Conversations, the token authorizes access to the underlying Chat Service. If you issued the token for the wrong service context or user, the connection can be denied.

• Generate a new Access Token on your server using your live Account SID, a valid API Key SID, and the matching API Secret. Do not use test credentials for Access Tokens. (help.twilio.com)
• Make sure the token includes the correct product grant and identity for the client you are connecting. For Conversations, use the correct Chat Service SID. For Sync, add the Sync grant before returning the token to the client.
• Pass the token to the SDK as the raw token string returned by your backend. If your backend responds with JSON, extract the token value before you initialize the client. (help.twilio.com)
• Refresh the token before it expires in long-running clients. Handle events such as tokenAboutToExpire, tokenExpired, or a Denied connection state, then request a fresh token and update the client.
• If the problem continues, verify that the user should be allowed to connect and that your backend is issuing a token for the correct account, service, and user identity.

• Access Tokens
• Create Access Tokens for Conversations
• Issuing Sync Tokens