AT command XBee from atmega to disable DIO5 (associated led)

I community! I need put ATcommand to my XBee from my atmega using a “xbee library” and a function that I have found in internet. I think the ATComand is “ATD50” to change the DIO5 to value “0” (disabled). My intention is to turn off a led connected into DIO5 (digital input/output 5 (associated led)) after X second/minutes of turning on the device (so that it doesn’t turn one again after initial check).

This is a part of my code:

#include <XBee.h>
XBee xbee = XBee();
uint8_t atdCmd[] = {'A','T','D','5','0'}; //<---command to put DIO5 to "0" (disabled)
AtCommandRequest atRequest = AtCommandRequest();
AtCommandResponse atResponse = AtCommandResponse();  
void setup()
{ 
delay(30000); 
atRequest.setCommand(atdCmd);
xbee.send(atRequest);
}
void loop()
{}

…but it doesn’t work! Thanks guys!