Today I encountered an error, when I tried to telnet to some windows machine, I got this error “Failure in initializing the telnet session. Shell process may not have been launched.”

I checked the configure of  the remote host and see that the telnet service has been started, so why failure?

I tried Google and found this solution: because if you telnet to this session, you are trying to make another logon, so you have to enable the “secondary logon” service.

I did that, and wow~, success !