Possible causes for this error message:
Problem: The KDC (Key Distribution Center) may not be running.
Solution: Confirm that the KDC is running.
Problem: You may need to enter a fully qualified host name.
Solution: Check your realm configuration. If necessary, enter a fully qualified host name.
Problem: The server's host may be down.
Solution: Verify that the server's host is running.
Problem: If you run the Kerberos client using an SLIP or PPP connection, and use DNS only for host name resolution, you may be having a timeout problem.
Solution: Try connecting again at a later time, or check to see whether the network is having problems.
Problem: You may need to run Kerberos 5 security server software.
Solution: Contact your Kerberos system administrator to verify that your system is running the appropriate security server software.
Problem: The setting may have been set to 0 for this KDC, which forces TCP protocol for all communications with the KDC. The KDC to which you are authenticating may require UDP protocol.
Solution: Set the to a value greater than 0.