Problem: The KDC could not find the host you requested in the principal database.
Verify that the host table (on the server and on the PC) contains the fully qualified name of the requested host.
Verify that the requested host name is entered correctly in the realm configuration.
Make sure that the requested host name is not an alias. You must use the actual host name (both in your request and in the realm configuration). Typically, you need to use the fully qualified host name (for example, telnserv.com instead of telnserv).
Double-check that you are using the correct ticket-granting ticket. Your TGT must be valid for the same realm as the host you're logging in to (unless your environment is set up for cross realm authentication).