IMessage won't sign in after upgrade to Mountain Lion

Question

Just upgraded from Lion to Mountain Lion. FaceTime and iMessages can't log me in. In iMessage Setup, I use my default AppleID and password (that I use on my other iOS devices), and it says "Could not sign in. Please check your network connection and try again".
I partook in the iMessages Beta programme (and uninstalled it months before Mountain Lion came out).
Also some other points:
* My time is set correctly
* My DNS resolvers are working (actually using 8.8.8.8)
* My certificate chain doesn't have any invalid or out of date certs
* I can log into iCloud (from Preferences panel) just fine
* I can log into the Mac App Store just fine
* I've tried clearing the relevant Cache/preferences *.plist files in ~/Library/[Preferences|Cache]/*
I noticed in the console logs this error that crops up all the time:
Jul 27 09:14:00 tinea-mac.local apsd[55]: Certificate not yet generated
as well as:
Jul 27 09:09:14 machine-mac.local apsd[55]: Got connection error Error Domain=NSURLErrorDomain Code=-1202 "The certificate for this server is invalid. You might be connecting to a server that is pretending to be <E2><80><9C>albert.apple.com<E2><80><9D> which could put your confidential information at risk." UserInfo=0x7fff39c2b0a0 {NSURLErrorFailingURLPeerTrustErrorKey=<SecTrust 0x7fff39a390b0 [0x7fff787d3190]>, NSLocalizedRecoverySuggestion=Would you like to connect to the server anyway?, NSUnderlyingError=0x7fff39a22a90 "The certificate for this server is invalid.
You might be connecting to a server that is pretending to be <E2><80><9C>albert.apple.com<E2><80><9D> which could put your confidential information at risk.", NSErrorPeerCertificateChainKey
=(
            "<SecCertificate 0x7fff39a1f450 [0x7fff787d3190]>",
            "<SecCertificate 0x7fff39a63eb0 [0x7fff787d3190]>",
            "<SecCertificate 0x7fff39a5b810 [0x7fff787d3190]>"
        ), NSLocalizedDescription=The certificate for this server is invalid. You might be connecting to a server that is pretending to be <E2><80><9C>albert.apple.com<E2><80><9D> which coul
d put your confidential information at risk., NSErrorFailingURLKey=https://albert.apple.com/WebObjects/ALUnbrick.woa/wa/deviceActivation?device=Mac OS, NSErrorFailingURLStringKey=https://albe
rt.apple.com/WebObjects/ALUnbrick.woa/wa/deviceActivation?device=MacOS, NSErrorClientCertificateStateKey=0}
Jul 27 09:09:14 machine-mac.local apsd[55]: Failed to get client cert on attempt 9, will retry in 900 seconds
Any ideas?

Answer 1

Well, I finally got this to work.  My symptoms were; after Mountain Lion install, I cannot log into iMessage, FaceTime or the App Store.   Getting many certificate errors from websites using Safari.  Console log shows various certificate error messages such as Failed to get client cert and Certificate not yet generated each time an Appleid login was attempted.
After carefully following these instructions, step by step fixing cirtificates in the System Root Folder of Keychain, it finally started working.  The first time I used these instructions I was apparently in the wrong Keychain Folder.
http://b.rthr.me/wp/?p=356
Cheers