If you are talking about CM 4.0 or CM 4.0.1, you need to go into the "Launch Maintenance Web Interface", click on "Server Access", then click on "enable" for the Telnet Server (23), and "enable" fot the SAT (Telnet 5023), then click on "submit".
By default, telnet is turned OFF on CM 4.0
I Always, Always always re-enable it. SSH is just too slow, and does not work all that well with some applications.
Hope this fixes your problem,
Mitch