How to solve the problem in firestore?

Question

JavaScript

Hello everyone, I get the following error in the console:
firebase-firestore.js:1 Uncaught (in promise) FirebaseError: Missing or insufficient permissions.
It appeared after the line:
db.collection("users").get().then(snapshot=>{
console.log(snapshot.docs);
});
What according to the Hindu from YouTube, according to the documentation, this error pops up. Don't know how to solve it?