I am new to AWS Lambdas - I am trying to write a lambda function to retrieve some data from firebase. I have called this function exports.handler and uploaded it to the Lambda with the node modules as a Zip file. However, when I try to run it, it returns the following error:

{
  "errorType": "Runtime.HandlerNotFound",
  "errorMessage": "index.handler is undefined or not exported",
  "trace": [
    "Runtime.HandlerNotFound: index.handler is undefined or not exported",
    "    at Object.module.exports.load (/var/runtime/UserFunction.js:144:11)",
    "    at Object.<anonymous> (/var/runtime/index.js:43:30)",
    "    at Module._compile (internal/modules/cjs/loader.js:1156:30)",
    "    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1176:10)",
    "    at Module.load (internal/modules/cjs/loader.js:1000:32)",
    "    at Function.Module._load (internal/modules/cjs/loader.js:899

Here is my function:

module.exports.handler = async (event) =>{
    ref.on("value", function(snapshot) {
        snapshot.forEach(function(childSnapshot) {
            responses.push({
                date: childSnapshot.val().Date,
                name:childSnapshot.val().name,
                response: childSnapshot.val().response
            })
        });
        printObjects(responses);
        console.log(json(responsesByPerson));
    })
})

I have looked at the other answers to questions similar to mine and implemented some of those solutions but none have worked.