Just at random without running any updates I am not able to sign in to iMessage or FaceTime ....- 10.12.3 MBP (Mid 2012) - All my other devices (iPad, iPhone, iMac ) are not effected , i can log into my iCloud account without any problems .... I have found this thread from march last year - https://www.macrumors.com/2016/03/23/mac-users-facetime-imessage-login-issues/ which is exactly the issue .... Anyone else having a problem ? or know how it can be resolved without a complete O/s install - Thanks J