The kerberos client received a KRB_AP_ERR_TKT_NYV error from the server %1. This indicates that the ticket used against that server is not yet valid (in relationship to that server time). Contact your system administrator to make sure the client and server times are in sync, and that the KDC in realm %2 is in sync with the KDC in the client realm.

Details
Product:	Windows Operating System
Event ID:	5
Source:	Kerberos
Version:	5.2
Symbolic Name:	KERBEVT_KRB_AP_ERR_TKT_NYV
Message:	The kerberos client received a KRB_AP_ERR_TKT_NYV error from the server %1. This indicates that the ticket used against that server is not yet valid (in relationship to that server time). Contact your system administrator to make sure the client and server times are in sync, and that the KDC in realm %2 is in sync with the KDC in the client realm.

Explanation
Kerberos cannot authenticate the Web program user because the time period for this service ticket has not started yet. The time on the server does not match the time on the Key Distribution Center (KDC) that issued the ticket, so the server does not recognize this as a valid ticket.

User Action
Ensure that the time on the server matches the time on the KDCs of its domain. For more information about Kerberos, see Kerberos Authentication in Windows Server 2003.