DHT11 can't read

Trying to read humidity and temp in a jar. Worked 20 minutes ago, but now all I get is:

{ "err": true, "checksumError": false,
  "raw": "",
  "temp": -1, "rh": -1 }
Temp is -1 and RH is -1

Any thoughts ?
Sensor hookup: Gnd = Gnd , Vcc = D1, DATA = D2

My code:

setWatch (function(){
digitalWrite(D1, 1);  
  var dht = require("http://www.espruino.com/modules/DHT11.js").connect(D2);
  dht.read(function (a) {
  console.log(a);
    console.log("Temp is "+a.temp.toString()+" and RH is "+a.rh.toString());

    if (a.rh > 70) {
      digitalPulse(LED1, 1, [2000]);
    }
    if (a.rh >= 60 && a.rh <= 70) {
      digitalPulse(LED3, 1, [2000]);
    }
    if (a.rh < 60 && a.rh != -1) {
      digitalPulse(LED2, 1, [200, 100, 200, 100, 200, 100, 200, 100, 200]);
    }
     if (a.rh === -1) {
      digitalPulse(LED1, 1, [200, 100, 200, 100, 200, 100, 200, 100, 200]);
    }
});
  setTimeout(function() {
  digitalWrite(D1, 0);
}, 7000);
}, BTN, { edge:"falling",repeat:true,debounce:50});