SEC_E_NO_CREDENTIALS error in AcquireCredentialsHandleA

Question

I need to implement TLS connection using certificates. but i am getting an error while calling a API AcquireCredentialsHandle() method.
 Error =  SEC_E_NO_CREDENTIALS

m_pSecurityFunc->AcquireCredentialsHandleA( NULL,

Does anybody has idea about SEC_E_NO_CREDENTIALS error. I have installed a proper certificate................

UNISP_NAME_A,SECPKG_CRED_OUTBOUND, NULL, m_pSChannelCred, NULL, NULL, m_phServerCreds, &tsExpiry);