I am calling a cloud function which runs a transaction, however it is returning an error to console which says:

Callable request verification passed {"verifications":{"auth":"VALID","app":"MISSING"}}

Googling it led me to App Check which is a new thing in Firebase. I am using React-Native firebase npm packages and following its documentation about App Check is extremely difficult due to lack of proper explanation and examples.

Below I have the code which I am trying to execute in the function:

const functions = require("firebase-functions");
const admin = require("firebase-admin");
admin.initializeApp();
const firestore_ = admin.firestore();
// const { CustomProvider } = require("@react-native-firebase/app-check");
const appCheckForDefaultApp = admin.appCheck();    
const GeoPoint = admin.firestore.GeoPoint;
const FieldValue = admin.firestore.FieldValue;    
const _geofirestore_ = require("geofirestore");
const GeoFirestore = _geofirestore_.initializeApp(firestore_);



exports.createNew = functions.runWith({
   allowInvalidAppCheckToken: true  // Opt-out: Requests with invalid App
   // Check tokens continue to your code.
}).region('europe-west6').https.onCall(async (data, context) => {

   try {

      //Checking that the user calling the Cloud Function is authenticated
      if (!context.auth) {
         return "The user is not authenticated: " + context.auth;
         // throw new UnauthenticatedError('The user is not authenticated. Only authenticated Admin users can create new users.');
      }

      const longitude = data.longitude;
      const latitude = data.latitude;
      const thirty_mins_old = data.thirty_mins_old;
      const currenttime = data.currenttime;

      const GeoFirestore_ = new _geofirestore_.GeoFirestore(firestore_);
      const sfDocRef = GeoFirestore_.collection('mycollection')
         .limit(1)
         .near({ center: new GeoPoint(latitude, longitude), radius: 0.05 });

      GeoFirestore.runTransaction((transaction) => {
         const geotransaction = new _geofirestore_.GeoTransaction(transaction, new GeoPoint(latitude, longitude));
         return geotransaction.get(sfDocRef._collectionPath).then((sfDoc) => {
            ...
         });
      });

   } catch (error) {
      if (error.type === 'UnauthenticatedError') {
         throw new functions.https.HttpsError('unauthenticated', error.message);
      } else if (error.type === 'NotAnAdminError' || error.type === 'InvalidRoleError') {
         throw new functions.https.HttpsError('failed-precondition', error.message);
      } else {
         throw new functions.https.HttpsError('internal', error.message);
      }
   }
});

EDIT: I am debugging the app so I am not working on production. Does debugging still requires this to be configured?