React Firebase endless loading

I'm using React-Firebase (https://react-firebase-js.com/docs/react-firestore-database/getting-started) for using firebase in my project.
I've followed the instructions and this should work:

<FirestoreCollection path="/posts/">
    {post => {
      return post.isLoading ? "Loading" : <BoardPost title={post.value} user="me" />;
    }}
</FirestoreCollection>

However, it shows an endless Loading text instead of the actual component.
And ideas on why this would happen?

My console shows no errors.