CC3220SF: sl_WlanPolicySet(..) returns code -14339 when called send time

Part Number: CC3220SF

I am calling

sl_WlanPolicySet(SL_WLAN_POLICY_PM, SL_WLAN_ALWAYS_ON_POLICY, NULL, 0);

function that returns -14339 when called for a second time after each other.

How to understand the return value? It is not documented in 'errors.h' in SimpleLink.

Thanks for any support.

Jiří