how can i force user login domain

hello
i have a LanEnforcer appliance,use PEAP authentication mode.

i want force users longin domain by LanEnforcer.i set "user authentication "condition as failed or unavailable,and other condition is ingore.when the user logon workgroup ,the port  not switch to specific Vlan.

i check Enforcer log and display the enforcer had enforce the correct role.

in the IAS log,it's warning "the authentication quest of the computername\workgroup user  had  gived up"

please  help me how can i force user login domain by lanenforcer.

Thanks

--noble