problem of interaction of two devices puck.js v2.1

Hello!
I am studying the interaction of two puck devices.js
I need to transfer data from one device to another.
I use tutorials from the Internet.
A strange error occurs at the getPrimaryService stage.

My Code:

var gatt;
NRF.requestDevice({ timeout: 5000, filters: [{ namePrefix: 'Puck.js 4bcd' }] }).then(function(device) {
   return device.gatt.connect();
}).then(function(g) {   
    gatt = g;  
    console.log("4");
return gatt.getPrimaryService("6e400001-b5a3-f393-e0a9-e50e24dcca9e");
}).then(function(service) {  
  console.log("5");
  return service.getCharacteristic("6e400002-b5a3-f393-e0a9-e50e24dcca9e");  
}).then(function(characteristic) {
  console.log("6");
  return characteristic.writeValue("LED3.set()\n");
}).then(function() {
  gatt.disconnect();
  console.log("OK!");
});

When I call this code

return gatt.getPrimaryService("6e400001-b5a3-f393-e0a9-e50e24dcca9e");

An error appears:

Uncaught Error: Unhandled promise rejection: ERR 0x11 (BUSY)

Execution stops, information does not go to the second device.
I don't understand what the problem is, I couldn't find an answer on the Internet.