OAuthException Error when accessing playlist

I'm logged using Firefox to both the main service (https://www.deezer.com/us/) and the developer portal (https://developers.deezer.com), and I used the API explorer available at: https://developers.deezer.com/api/explorer

When I click the "Playlist" tab, I always get this error:

(BTW the playlist I want to access is https://api.deezer.com/playlist/908622995)

{
  "error": {
    "type": "OAuthException",
    "message": "An active access token must be used to query information about the current user",
    "code": 200
  }
}

(of course I have a pay subscription)

I planned to develop something using the Deezer API but I don't know how to get rid of this error. Any suggestions?