I am using LogonUser function to logon an account to Windows 2008 R2 server on a domain with clusterring. When using LOGON32_LOGON_INTERACTIVE as LogonType, I successfully login. When using LOGON32_LOGON_SERVICE as LogonType, Login fails, EventViewer says: An account failed to log on. Logon Type: 5 Account For Which Logon Failed: Security ID: NULL SID Account Name: thename Account Domain: thedomain Logon ID: 0x1009371c Logon Type: 5 Failure Information: Failure Reason: The user has not been granted the requested logon type at this machine. Status: 0xc000015b Sub Status: 0x0 Was not sure if its for superuser or stackoverflow (calling LogonUser from C# code), but I guess its some Windows server issue*. EventID = 4625 Edit: Found that - 0xc000015b The user has not been granted the requested logon type (aka logon right) at this machine Edit: Should be serverfault question...