Hi,

smartcard login consists on CAPI2. To enable verbose debugging set the loglevel and start the logging

D:\> reg add HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\crypt32 /v DiagLevel  /T REG_DWORD /d 5 /f
D:\> reg add HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\crypt32 /v DiagMatchAnyMask /T REG_QWORD /d 0x00ffffff /f
D:\> wevtutil.exe sl Microsoft-Windows-CAPI2/Operational /e:true 

Details will be found in the Microsoft-Windows-CAPI2/Operational log.

Here you find further details on debugging/tracing smardcard issues.

Michael