Currently Being ModeratedSep 20, 2013 9:22 AM (in response to ewela)
I had the same problem. Here is what worked for me: log in with a different account and switch back.
I have several Apple accounts and use my old gmail-address for all the iTunes purchases. Tried to log in with no success.
Then I tried my icloud-account and was able to log in instantly. Logged out and tried the old gmail-account and logged in successfully.
Juchuu (like the Germans would say)!!!
Currently Being ModeratedSep 30, 2013 8:56 AM (in response to ewela)
I had the same issue and have now solved it.
Hope this helps,