Rejected an insecure guest logon. User name: %2 Server name: %4 Guidance: This event indicates that the server attempted ...

Rejected an insecure guest logon.

User name: %2
Server name: %4

Guidance:
This event indicates that the server attempted to log the user on as an unauthenticated guest and was denied by the client. Guest logons do not support standard security features such as signing and encryption. As a result, guest logons are vulnerable to man-in-the-middle attacks that can expose sensitive data on the network. Windows disables insecure guest logons by default. Microsoft does not recommend enabling insecure guest logons.