to make a short summary, my brother took back his account to give it to me, since a new server (STELERIO) opened in France... So I have the Premium Launcher, a Premium Account but I can't run any premium servers and it says "Failed to login : The authentification servers are currently down for maintenance  ". I went to the latest logs and I saw a thread/info about it

here it is :

[19:42:40] [Client thread/INFO]: Stopping!
[19:42:40] [Client thread/INFO]: SoundSystem shutting down...
[19:42:40] [Client thread/WARN]: Author: Paul Lamb, www.paulscode.com

By the way, my skin isn't applied even if I choose him in the launcher : I think my premium account is considered as a crack one...