Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays

I am trying to retrieve data from firebase and display them.

But I kept getting that error.

my part of code is like this:

-firebase service file-
profileData: FirebaseObjectObservable<Profile[]>;

getProfile() {
return this.profileData = this.afDatabase.object(’/profile/’);

-homepage ts file-

profiles: FirebaseObjectObservable<Profile[]>;

ionViewWillLoad() {
this.profiles = this.firebaseService.getProfile();
console.log(‘ionViewDidLoad HomePage’);

-homepage template-
<ion-item *ngFor="let profile of profiles | async " >
{{profile.username }} - {{profile.category }} - {{profile.goal}} - {{profile.level}}

I looked up several similar problems discussed here but
I can’t solve mine following their solutions.

I am working on this problem several days.
Please help me.