How do I can get current player highscore from Google Play Service?

I try to get the highscore of the current player from the Google Play service, and it shows me "0". But player details (ID and display name) display correctly.

I can see my real highscore only at the native leaderboard popup (internal test version published to Google Play).

I use the Google Play plugin

construct.net/en/make-games/addons/23/google-play

What did I do wrong?