GameCenter authentication request was cancelled!

Ha, the odd thing is after I authenticated using " Social.localUser.Authenticate (ProcessAuthentication);". The log told me request was cancelled. So the authentication was failed either.
Should I set provision or something else?

I found the answer myself. Because I have logged in my account in normal GC. But the app needs the sandbox GC. So, after I log out from normal GC, everything works perfect again.
Hope this is helpful.