FirebaseListAdapter not showing database results android

Question

I am making a chat app on Android that uses google firebase to store messages that users write to each other. To display these messages to the users I read them from the database and organize them into a custom ListView with a ListAdapter.

I'm using com.firebaseui:firebase-ui:3.1.3

the problem is that the list view is always empty, the FirebaseListAdapter is not showing database results

private void displayChatMessages() {

    Query query = FirebaseDatabase.getInstance().getReference();
    FirebaseListOptions<ChatMessage> options = new FirebaseListOptions.Builder<ChatMessage>()
            .setQuery(query, ChatMessage.class)
            .setLayout(R.layout.community_message)
            .build();

    adapter = new FirebaseListAdapter<ChatMessage>(options){
        @Override
        protected void populateView(View v, ChatMessage model, int position) {
            TextView messageText = (TextView)v.findViewById(R.id.message_text);
            TextView messageUser = (TextView)v.findViewById(R.id.message_user);
            TextView messageTime = (TextView)v.findViewById(R.id.message_time);

            messageText.setText(model.getMessageText());
            messageUser.setText(model.getMessageUser());

            messageTime.setText(DateFormat.format("dd-MM-yyyy (HH:mm:ss)",
                    model.getMessageTime()));
        }
    };

    listOfMessages.setAdapter(adapter);

}

public class ChatMessage {

    private String messageText;
    private String messageUser;
    private long messageTime;

    public ChatMessage(String messageText, String messageUser) {
        this.messageText = messageText;
        this.messageUser = messageUser;

        // Initialize to current time
        messageTime = new Date().getTime();
    }

    public ChatMessage(){

    }

    public String getMessageText() {
        return messageText;
    }

    public void setMessageText(String messageText) {
        this.messageText = messageText;
    }

    public String getMessageUser() {
        return messageUser;
    }

    public void setMessageUser(String messageUser) {
        this.messageUser = messageUser;
    }

    public long getMessageTime() {
        return messageTime;
    }

    public void setMessageTime(long messageTime) {
        this.messageTime = messageTime;
    }
}