Firebase search?

Question

JavaScript

I have many users in the Users/ branch, I need to find one of them by user_email and, for example, change the status.

Here is my code but it doesn't work for some reason...

firebase.database().ref('Users').orderByChild('user_email').equalTo(email).once('value').then(function(snapshot) {
    var key = snapshot.val()
    alert(key);
 })