Scan policy on ap mode problem

Hi 

     I can get the scan results on STA mode. But when i set CC3200 to AP mode. And then call scan policy, that will be failed. Why?

lRetVal = sl_WlanPolicySet(SL_POLICY_SCAN , ucpolicyOpt,
(unsigned char*)(policyVal.ucPolicy), sizeof(policyVal));
if(lRetVal!=0)
{
UART_PRINT("Unable to set the Scan Policy\n\r");
return lRetVal;
}

It always get failed on sl_WlanPolicySet method. Can it only work on STA mode for Scan policy?

Best Regards!

James