After doing a clean install of Mountain Lion on my MacBook Pro (13" unibody, MacBookPro5,5) and upgrading to 10.8.3 I'm having trouble with iMessage, Facetime and Back to My Mac. I am running Little Snitch (version 3.0.4) though turning it on or off has no effect on these results. My Apple ID works for other services.
System Preferences > iCloud: Turning on Back to My Mac gives the error "iCloud server not responding." (though it didn't seem to try very hard, looking at the network monitor)
iMessage: Attempting to sign in yields "Could not sign in to iMessage. Could not sign in. Please check your network connection and try again."
FaceTime: Attempting to sign in yields "Could not sign in. Please check your network connection and try again."
I've tried the following:
- Checked that my time is set, in the correct time zone, and set to automatically set itself.
- I checked Keychain Access > System for any Back to My Mac keys to delete. None present.
- I have no entries in /private/etc/hosts for *.apple.com or for *.verisign.com.
Of note: the serial number listed in About this Mac/System Information is incorrect and does not match the SN on the case (off by one letter--I think it was serialized incorrectly once after the logic board was replaced once). Would this affect iMessage/iCloud in Mountain Lion? It worked in Lion despite this. Sadly I am out of AppleCare coverage, but maybe a Genius would see the fault is Apple's and re-serialize the board.