OS X 10.11.6 (also on facetime). Sometimes asks to resubmit password to icloud in system preferences, which does not help. Can not use imessage as will not accept password. Tried incorrect password and it does notice it is wrong, therefore not a matter of an incorrect password. (IOS is fine)
Hello jefflemac,
Thanks for reaching out to the Apple Support Community. I know how important it is to be able to access all the services on your Apple devices. I use them all every day. It sounds like your Mac is having hard time re-establishing a connection to iCloud. If you've already confirmed your password works it may help to simply sign your Mac out entirely, then restart and sign back in. That way you know you have a solid fresh connection.
To sign out you can go to your system preferences and clicking on the iCloud icon. Once you've selected sign out it will ask you if you want to keep or delete certain information on your mac. When given he option be sure to select "Keep on my Mac"
Once you are signed out, restart and sign back in. If the behavior persists the entire community is here to help.
-Best Regards
I have this problem on my MacPro as well. I have tried restarting the computer, tried signing out of iCloud and just about everything else I can think of to no avail. iMessage works fine on my MacBookPro running 10.11.6 which is the same version as on my MacPro. This seems to me a common problem and there is no useful response from Apple yet.
imessage: an error occurred during authentication. OS X 10.11.6 (also on facetime)
