errorMessage: "Error: ENOENT: no such file or directory, open '/var/task/credentials.json'" errorType: "Runtime.UnhandledPromiseRejection"

I am working on a Next JS app using google Sheet api for a personal project. Now this works completely fine on my local. But when I am deploying it to Netlify, this error pops up.

Can someone put up a solution? Thanks!

Here is my code:

import { google } from "googleapis";

export default async function form1(req, res){

    if (req.method === 'POST') {
        // Process a POST request
        console.log("POST hit")
        const auth = new google.auth.GoogleAuth({
            keyFile: "credentials.json",
            scopes: "https://www.googleapis.com/auth/spreadsheets",
        })

        //create client instancce
    const client = await auth.getClient();

    //instance of google sheet api

    const googleSheets = google.sheets({version: "v4", auth: client});


    const spreadsheetId = "*********55653"

    //Write rows TO sheet
    const {name, email, phone} = req.body;

    await googleSheets.spreadsheets.values.append({
        auth,
        spreadsheetId,
        range:"Subs!A:B",
        valueInputOption: "USER_ENTERED",
        resource: {
            values: [
                [name, email, phone]
            ],
        }
    })

    res.send("Success")
      } else {
        // Handle any other HTTP method
        res.status(405)
      }


}