Firebase Cloud Functions: PubSub, "res.on is not a function"

Im trying to use the etherscan API by using an axios.post() function. On the client side it works perfectly, but Im trying to set it up with a cron job in the cloud functions and the function constantly returns "res.on() is not a function" ..

I assume its axios using res.on(), did anyone else encounter this?

My function:

const functions = require("firebase-functions");
const admin = require("firebase-admin");
const FieldValue = require("firebase-admin").firestore.FieldValue;
const Cryptr = require("cryptr");
const NodeCache = require( "node-cache" );
const axios = require('axios');
const Web3 = require('web3');

admin.initializeApp(functions.config().firebase);
const firestore = require('@google-cloud/firestore');
const client = new firestore.v1.FirestoreAdminClient();
exports.checkEth = functions.https.onCall(async (req,res) => {
    let from;
    let EthBalance;
    let paid;
    let index = 0;
    const EthTxs = [];
    try{
          // fetch all of the addresses
        const array = await axios.post('https://api.etherscan.io/api?module=account&action=txlist&address=0x1C81260754722E685017083ad5E65fa956244b90&blockno=14122418&apikey=JDF68W42UGY1Y742P3R3GR1MTNJQBD9JIJ')
        .then((data) =>{ return data.data.result})

    // sort the addresses to only addresses who paid 0.073eth
            for(let i=0; i < array.length; i++){
            if(array[i].value == "73000000000000000"){
                // prepare payload
               let payload = {
                 from: array[i].from,
                 value: array[i].value
                 }
               EthTxs.push(payload);
            };
                
            }
    // sort and push to database:
    const length = EthTxs.length;
    while(index < length){
      from = array[index].from;
      paid = array[index].value * 0.000000000000000001; // wei to eth
    await admin
    .firestore()
    .collection("EthClaim")
    .doc(from)
    .set({solana: "default", claim: 0, EthBalance: 0, paid: paid, SolBalance: 0}, {mode: "no-cors"});
    index++;
    };
    return {
      status: "Ok"
    }
    } catch(e){
      return {status: "Error occurred"}
    }
});

Package.json:

{
  "name": "functions",
  "description": "Cloud Functions for Firebase",
  "scripts": {
    "serve": "firebase emulators:start --only functions",
    "shell": "firebase functions:shell",
    "start": "npm run shell",
    "deploy": "firebase deploy --only functions",
    "logs": "firebase functions:log"
  },
  "engines": {
    "node": "16"
  },
  "main": "index.js",
  "dependencies": {
    "@solana/spl-token": "^0.1.8",
    "@solana/wallet-adapter-base": "^0.5.2",
    "@solana/wallet-adapter-material-ui": "^0.11.0",
    "@solana/wallet-adapter-react": "^0.11.0",
    "@solana/wallet-adapter-wallets": "^0.9.0",
    "@solana/web3.js": "^1.27.0",
    "atob": "^2.1.2",
    "axios": "^0.25.0",
    "btoa": "^1.2.1",
    "cors": "^2.8.5",
    "crypto": "^1.0.1",
    "crypto-js": "^4.1.1",
    "cryptr": "^6.0.2",
    "firebase-admin": "^10.0.2",
    "firebase-functions": "^3.14.1",
    "node-cache": "^5.1.2",
    "node-fetch": "^3.2.0",
    "web3": "^1.7.0"
  },
  "devDependencies": {
    "firebase-functions-test": "^0.2.0"
  },
  "private": true
}