Question from a developer:
I'm trying the Leaderboard API (https://api.playfab.com/Documentation/Client/method/GetLeaderboard) via the "Try It" option in the documentation, but it's returning no results (below) - why is that?
```
{
"code": 200,
"status": "OK",
"data": {
"Leaderboard": []
},
"CallBackTimeMS": 78
}
```