Apple-TV is showing the good internet connection, has updated the software from the internet, but is not able to connect to iTunes store.

Hi there.

My apple TV was working perfectly 2 months ago, I stopped using it and came back now. But now suddenly it's not connecting to the iTunes store or the home-sharing computer. I have restored it and set-up everything from the beggining:

1. I opened my home computer iTunes and turned on home-sharing.
2. I shared a library with songs and videos from my home storage.
3. I played a song from the home-computer through the air-play on the apple-TV and it played perfectly!
4. I came to my apple-TV and tried to set it up - the software was downloaded perfectly from the wireless internet connection.
5. I tried testing the connection on the apple-TV and was asked to access the iTunes store. I put my apple-id and password and the apple-TV said: "cannot connect to iTunes store".
6. I tried to connect to my home-computer through the home-sharing (and as I wrote before - the apple-TV played perfectly a song that was played on the home computer) - I put my apple-id and password and the apple-TV said: "unable to sign in".
7. I tried reseting my apple TV, reseting my internet router - but nothing worked.

Any suggestions?