Game Center and iCloud server issues

Hi there,

After having installed Mountain Lion just a few hours ago, I seem to have trouble with iCloud.

• The Game Center app will not let me log in, stating "Could not connect to Game Center server"
• Back to my Mac in the iCloud settings panel will not let me log in either, stating: "iCloud server not responding"
• Messages will not accept my iMessage account either - stating: "Could not log in. Please check your network connection and try again."
• iTunes has no problems logging in to the iTunes Store etc.
• the mac App Store seems to work fine logged in as well.

I have tried the other fixes people have suggested here already -

• reverting the hosts file to its default state and flushing the dns
• repairing disk permissions via disk utility
• deleting a few keychain entries regarding back to my mac.

there are other entries in the keychain app that are appleid related, can this be the issue?

Any thoughts are much appreciated!

-Henrik