NPS Audit Failure in 802.1x authentication

Question

I am working on configuring the NPS on windows server for making it to do 8021.x authentication.

But, after the configuration is done, terminal device trigger the 802.1x authentication process, and get the failure response. In the windows server side, there is Event with ID 6273 in the Event View.

The detailed info is as below.

	Authentication Type:		EAP
	EAP Type:			Microsoft: Smart Card or other certificate
	Account Session Identifier:		-
	Logging Results:			Accounting information was written to the local log file.
	Reason Code:			293
	Reason:				The certificate is not valid for the requested usage.

I don't know why the Windows server think the certificate is not valid for the requested usage.

Hope you can provide some help.

Thanks.