Problem with EAP TLS authentication in Freeradius

Hi, Iam using Freeeadius 2.1.0. The setup is working fine with EAP-TTLS, PEAP method.But for EAP TLS, it gives the below error.. Please let me know how to solve.. [eap] Handler failed in EAP/tls [eap] Failed in EAP select ++[eap] returns invalid Failed to authenticate the user. Regards Senthil