Can't Login.

I am a Chinese guy, and my English is really poor
Most recently , every time I logined the Launcher , it told me "Invalid username or password". But I'm not wrong, and I can login at the website.
I'd searched for the solution, someone said that revise the HOSTS can solve this problem, and it worked! HOWEVER I can't pass the authentication of servers, told me that the authentication servers are currently down for maintenance, but other guy were playing! And I called my Network operators, they said it's not their fault.
This problem led me nearly a month did not play MINECRAFT with my friends. It seems that there are other players are also encountered such trouble.