Adding firebase firestore entry failed : 7 PERMISSION_DENIED

I'm trying to use a Firebase Cloud Function to create a document within the Firestore database from my Node js environment with Express js, but it fails with below error on the function logs.

Error: Process exited with code 16
at process.on.code (/layers/google.nodejs.functions-framework/functions-framework/node_modules/@google-cloud/functions-framework/build/src/invoker.js:275:22)
at process.emit (events.js:198:13)
at process.EventEmitter.emit (domain.js:448:20)
at process.exit (internal/process/per_thread.js:168:15)
at Object.sendCrashResponse (/layers/google.nodejs.functions-framework/functions-framework/node_modules/@google-cloud/functions-framework/build/src/logger.js:37:9)
at process.on.err (/layers/google.nodejs.functions-framework/functions-framework/node_modules/@google-cloud/functions-framework/build/src/invoker.js:271:22)
at process.emit (events.js:198:13)
at process.EventEmitter.emit (domain.js:448:20)
at emitPromiseRejectionWarnings (internal/process/promises.js:140:18)
at process._tickCallback (internal/process/next_tick.js:69:34) 

firebase.ts file :

import * as admin from 'firebase-admin'
import * as functions from 'firebase-functions'

admin.initializeApp({
  credential: admin.credential.cert({
    privateKey: functions.config().private.key.replace(/\\n/g, '\n'),
    projectId: functions.config().project.id,
    clientEmail: functions.config().client.email
  }),
  databaseURL: 'https://app-id.firebaseio.com'
})

const db = admin.firestore()
export { admin, db }

controller.ts :

import { Response } from 'express'
import { db } from './config/firebase'

type EntryType = {
  title: string,
  text: string,
}

type Request = {
  body: EntryType,
  params: { entryId: string }
}

const addEntry = async (req: Request, res: Response) => {
const { title, text } = req.body
try {
  const entry = db.collection('entries').doc()
  const entryObject = {
    id: entry.id,
    title,
    text,
  }

  await entry.set(entryObject).catch(error => {
      return res.status(400).json({
        status: 'error',
        message: error.message
      })
    })

  return res.status(200).json({
     status: 'success',
     message: 'entry added successfully',
     data: entryObject
  })
 } catch(error) {
    console.log(error);
    return res.status(500).json(error.message) 
 }
}

Im receiving below response from this trigger :

{
    "status": "error",
    "message": "7 PERMISSION_DENIED: Invalid project number: 113102533737774060828"
}

Is this related to the Cloud Firestore rules in the Google cloud? Im fairly new to Google cloud functions. Any suggestions would be appreciated.