Firestore v9 Expected first argument to collection() to be a CollectionReference, a DocumentReference or FirebaseFirestore

I tried to add new users from the signup page to firestore but it didn't work.

Here's my config.js

import { initializeApp } from 'firebase/app';
import { getAuth } from 'firebase/auth';
import { getDatabase } from "firebase/database";

const firebaseConfig = initializeApp ({
  //cred
});

export const auth = getAuth(firebaseConfig)
export const database = getDatabase(firebaseConfig);

And Signup.js

import React, { Component } from "react";
import  firebase  from "./config";
import { collection, addDoc,doc } from "firebase/firestore"; 

class Signup extends Component {

    constructor(props) {
        super(props);
        this.state = {
            name: '-',
            email: '-',
        };
    }

    addUser = e => {
        e.preventDefault();

        try {
            const collectionRef = doc(database, 'users');
            const docRef = addDoc(collectionRef, {
                name: this.state.name,
                email: this.state.email,
            });
          } catch (e) {
            console.error("Error adding document: ", e);
          }

    render(){
        return (
            <div>
              //do something
              <button className="btn btn-primary" onClick={this.addUser}>Submit</button>
            </div>
    )}
}

And here's the error:

FirebaseError: Expected first argument to collection() to be a CollectionReference, a DocumentReference or FirebaseFirestore

I changed Config.js to:

export const auth = getAuth()
export const database = getDatabase();

and I still got the same error. Does it mean that I didn't connect firestore successfully? :'( Please help me solve this problem. Thank you.