Connecting TTN to Thingspeak (Receiving NULL values)

I am able to receive data from node on TTN. I have setup a webhook with thingpeak and it is healthy state but it is receiving all fields as NULL.
Below is code that I have entered in the payload formatter uplink by refering to Thingspeak Documentation

function Decoder(b, port) { 
  let var1 = (b[0]<< 8|b[1])/1000;
  let var2 = b[2];
  let var3 = (b[3]<< 8|b[4])/100;
  let var4 = (b[5]<< 8|b[6])/10;
  let var5 = (b[7]<< 8|b[8])/10;
  let var6 = (b[9]<<8|b[10])/10;
  let var7 = (b[11]<<8)|b[12];
  let var8 = (b[13]<<8)|b[14];
  let var9 = (b[15]<<8)|b[16];

  return {
    field1: var1,
    field2: var3,
    field3: var4,
    field4: var5,
    field5: var6,
    field6: var7,
    field7: var8,
    field8: var9,


This is the channel where I am receiving data regularly i.e every minute, but it has all null values.
Need help

Tried this as well but did not work