Issue:
The following error may occur when Cisco switches/routers use Windows 2003 servers as their time source.
148283 21:19:00.5472044s - Logging warning: NtpServer encountered an error while validating the computer account for client 10.126.2.15:123. NtpServer cannot provide secure (signed) time to the client and will ignore the request. The error was: The specified user does not exist. (0x80070525)
Cause:
The Cisco IOS has a known bug.
Bug Details for CSSdk11847.
Title: Signed vs. Unsigned problem introduced in NTP
Versions: 11.3 and 12.0 of the Cisco IOS will not synchronize NTP.
Solution:
Upgrade the Cisco IOS to a version that does not have this issue.