10.9: FaceTime and iMessage won't let me sign in

Hi,

I have installed the official Mavericks release (update from Lion) on my MB Pro (2011).
I can't sign in into FaceTime or iMessage (it tries for more than a minute, then I get an error message). Other iCloud functions work perfectly (mail, calendar, docs...).

Many online proposed fixes date back from Mavericks previews... I tried those unsuccessfully:
- Changing my iCloud password.
- Ensuring time and date are automatically set
- Editing the "hosts" file
- Changing my DNS to 8.8.8.8
- Resetting iCloud docs (on iCloud.com)
- Repairing permissions
- Connecting from another place (other ISP, router)
- In iMessage, signing in from "Preferences>Accounts"
- Signing in with a "@icloud.com" alias (my .mac address is still my iCloud login/Apple ID).

NONE of the above worked

Any idea will be welcome!

vtstarck said:

I'm having the same problem. I posted it in the Apple Communities site and a couple others are having the issue too.

https://discussions.apple.com/message/23486024?ac_cid=op123456#23486024

Click to expand...

Thanks, I hadn't seen this thread.
At least by now we can probably exclude the "wait a little fanboy, servers are overloaded" explanation

Well, maybe there is an explanation here:
https://discussions.apple.com/message/1219096#1219096

For some people, it seems to be related to the absence of the computer serial number in the "about my mac" section.
I am exactly in this case: my motherboard was exchanged by an Apple Reseller 2 years ago. Since then, the serial nr of the motherboard never appeared. I thought: ah well, doesn't matter.
But maybe this causes an authentication issue now...

Are you in the same situation Vtstarck?

EDIT November 2nd:
I did go to an Apple Care center, asked the guy to correctly set my logic board serial # (it takes 2 minute for them). He did (unwillingly), and guess what: problem solved, FaceTime and iMessage are now working perfectly.