When using SASL authentication (Kerberos V5), the following error appears in the log file:
(Active Directory) Authenticating user "..." using SASL mechanism "GSSAPI" with KDC address "..." and realm "..."...
(Active Directory) Successfully established a new connection to "...".
Above message may appear multiple times.
(Active Directory) Failed to authenticate user.
FME Server did not have the right privileges to find the user. This may be caused by the service account setting 'Do not require Kerberos preauthentication'.
Kerberos pre-authentication must be enabled for the service account. See Updating the Windows Domain Configuration for information on how to configure the service account.