TM4C1294NCPDT: DNS Resolve

Part Number: TM4C1294NCPDT

Hi,

Controller : TM4C1294NCPDT
RTOS : tirtos_tivac_2_01_00_03
IDE : CCS v8.3.1

I am trying to get ipv4 address by providing Domain Name using below mentioned ndk library func, but operation is getting failed with an Error code 19 
int DNSGetHostByName(char *Name, void *pScrapBuf, int size);

.cfg File
var Ip = xdc.useModule('ti.ndk.config.Ip');

Ip.autoIp = true;

var Http = xdc.useModule('ti.ndk.config.Http');

var http0Params = new Http.Params();
var http0 = Http.create(http0Params);

var Global = xdc.useModule('ti.ndk.config.Global');

Global.IPv6 = false;

Global.networkIPAddrHook = "&mynetworkIPAddrHook";
Global.networkOpenHook = "&functionNetworkOpenHook";

Global.lowTaskPriLevel = 3;

Global.stackInitHook = "&AddWebFiles";
Global.stackDeleteHook = "&RemoveWebFiles";

var Dns = xdc.useModule('ti.ndk.config.Dns');

Dns.externDnsServIp = "8.8.8.8";

Test Code :

Void ethTcpTaskFxn(UArg arg0, UArg arg1)

{

            char pc_buf[512 + 1] = "\0";
            int32_t i32_retCode = -1;

            while(1)
            {
                i32_retCode = -1;
                memcpy(pc_buf, '\0', sizeof(pc_buf));

                i32_retCode = DNSGetHostByName("cellcommsolutions.in", &pc_buf, sizeof(pc_buf));

                System_printf("%sI,%s,%s,i32_retCode = %d [%s]",
                                CSV_DEBUG_MSG_PREFILL_HEADER, __FILE__, __func__,
                                i32_retCode, pc_buf
                            );

                Task_sleep(5000);
            }

}

Please guide, if anywhere it is getting wrong either in code or .cfg file

Thanks