RAK8212 -BG96 can't register to network

I used your reference codes to test BG96 functions , we always meet some errors like " NO SERVICE " , can some one help us?

QNWINFO: NO SERVICE

CSQ: NOSERVICE

function testAT(command) {

console.log("Connectingular Modem ...");
require("iTracker").setCellOn(true, function (usart) {
  console.log("Cellularm connected.");
 setInterval(toggle1, 1000);
  at = require("AT").connect(usart);
  sendAtCommand("AT+GMR");
  //sendAtCommand('ATE0');
  //Singtel – Singapore (CAT-M1)
  sendAtCommand('AT+QCFG="band",0,4,80,1'); 
  sendAtCommand('AT+QCFG="nwscanseq",030102,1');
  sendAtCommand('AT+QCFG="nwscanmode",3,1');
  sendAtCommand('AT+QCFG="iotopmode",0,1');
  sendAtCommand('AT+CGDCONT=1,"IP","internet.iot"'); 
  sendAtCommand('AT+CGREG?'); 
  sendAtCommand('AT+CTZU=1'); 
  setTimeout(function () {
    checkStatus(); 
  }, 5000);
});
}
function checkStatus(command) {

 console.log("checkStatus------->");
  sendAtCommand('AT+CFUN=1');    
 sendAtCommand('at+cpin?'); 
  sendAtCommand('AT+COPS?');
  sendAtCommand('AT+CEREG=2');
  sendAtCommand('AT+CEREG?');
  sendAtCommand('AT+QNWINFO'); // network information
  sendAtCommand('AT+QSPN'); //registered network
  sendAtCommand('AT+QCSQ'); // signal strength
}

1 Attachment

• RAK_CATM1_Singtel.js