I am using Socket.io to connect BE and FE, and in each connection, the BE will verify the token sent from FE, and if the authentication fails, the connection will be cut up.

I am wondering, when a connection is cut up because of failed authentication, what should be returned from BE to FE by the software development industry standard?

```
  jwt.verify(token, process.env.JWT_SECRET, function (err, decoded) {
    if (err) {
      // Authentication failed, what should I do here?
      socket.disconnect();
    } else {
      // Authentication passed, do something.
      });
    }
  });

```

Thanks!