DNS_QUERY_FAILED in Windows Network

I try to use dns in conjunction with a dhcp. In some network I get error DNS_QUERY_FAILED when trying nx_dns_host_by_name_get()

I use the following code:

...

status = nx_dhcp_user_option_retrieve( &g_dhcp_client0, NX_DHCP_OPTION_DHCP_SERVER, dnsIpString, &dnsIpSize);

dnsIpAdr = nx_dhcp_user_option_convert( dnsIpString );

dnsIpAdr = __REV(dnsIpAdr);     // convert big endian to little endian

status = nx_dns_server_add(&g_dns0, dnsIpAdr);

status = nx_dns_host_by_name_get(&g_dns0, cloudSvrUrl, &cloudSvrIpAdr, 500);

    if(NX_SUCCESS != status) {
        g_ioport.p_api->pinWrite(Leds.p_leds[BSP_LED_LED2], IOPORT_LEVEL_LOW); // LED red
        printf(" ERROR: DNS Server add Error Code 0x%X \n", status);
        while(1);
    }

in a case were

 assigned IP address 192.168.1.101
 assigned Netw Mask 255.255.255.0
 assigned Gateway address 192.168.1.100

1 DNS IP address 192.168.1.100

it works BUT if I have:

 assigned IP address 192.168.8.136
 assigned Netw Mask 255.255.255.0
 assigned Gateway address 192.168.8.1

 1 DNS IP address 192.168.7.129

Administrator told me that host name is wrong in DHCP/DNS

Please help