Active Directory Certificate Services did not start: The Certificate Date Validity Period string in the registry value H ...

Active Directory Certificate Services did not start: The Certificate Date Validity Period string in the registry value HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\CertSvc\Configuration\%1\ValidityPeriod is invalid.  Valid strings are "Seconds", "Minutes", "Hours", "Days", "Weeks", "Months" and "Years".