A request was received by the RPC server on %1 endpoint from %2. The request was received on unauthenticated channel but ...

A request was received by the RPC server on %1 endpoint from %2. The request
was received on unauthenticated channel but the registered endpoint requires 
that the request be made over authenticated channel. This request will be 
ignored. The binary data contains the first 32 bytes of the request.