Q: Unable to sign into iMessage after El Capitan upgrade

Tried this and it didn't work. Called Apple Support and they bumped my case to engineering

I solved this by doing a lock keychain in keychain. Then click unlock in keychain. If you then go into the account from Messages and do sign-in it will prompt the login again and all works again.

In my case, what worked was to "change" the keychain password (Edit -> Change password for keychain "login") and set the same current password.  After that, every thing started to work ok:

1. Facetime

2. iCloud

3. Facetime account

The only thing still doesn't work is showing stored passwords on the keychain.  It doesn't show any error, buit it doesn't accept the login keychain password neither.

It's interesting this theory of the "over zealous" proceedure that "locks" one out of iMessage.

My experience shows that it may work at the AppleID level, as well as at the host/computer level.

I started having problems with iMessage when I returned from a overseas trip where I swapped my SIM card on my iPhone. This *$@#$#@ association that iMessage forces itself to assume the iPhone number identity by default causes my regular phone number to be dropped from iMessage the the new (overseas) number to take its place. First problem here is that anyone sending you messages to you phone number will not reach you, but that's not the issue here (WhatsApp asks if you want to switch the numbers, something that iMessage could do too).

When I got back home I returned to "default" SIM card and phone number. After a few days my nightmare started. I use iMessage on 3 Macs, iPhone and iPad, all with the same AppleID. Slowly they all begin to fail, starting with the iPhone. The interesting is that after a few attempts, it seems to block the computer from using ANY AppleID. After a several more tries, it's refusing to authenticate for iMessage and FaceTime (but authenticates for iCloud, iTunes and iBooks - interesting those are the services with a revenue stream for Apple )

And my experience with Apple support matches what was described. Called, got to level 1, lots of patience here, got transferred to level 2 (senior support) and they threw the towel and handed it to engineering.

Maybe they will do something, maybe it will "reset" by it's own. Let's wait and see. I will post the results (if and when it gets fixed).

For me it's some failed heuristics attempting to determine invalid usage of one's iMessage/FaceTime account, forcing the user to this nightmarish long proceedure to have someone look over. Apple has already set a page to remove the phone number association from iMessage. They could add a full reset (removal of all devices associated, email, Apple IDs, etc).

This work for me. I have a feeling this is cause of all my problems.  Can someone tell me why this works?    Thanks

HI,

You may need this page https://selfsolve.apple.com/deregister-imessage

Treat the old SIM as if it were and Old phone.

8:42 pm      Sunday; November 22, 2015

Hi,

Probably deleting all the com.apple. items from the Keychain is over the top but the action is a bit like deleting .plists where if the info is not there the app treats it a little like "First Run" and recreates fresh items which would include items for Messages and the iMessages account.

iMessages only uses the IDS items in the Keychain (As does FaceTime).

Messages as a whole will use other Application Passwords listed in the Keychain possibly for AIM, Jabber, Google and/or Yahoo.

8:46 pm      Sunday; November 22, 2015

That would be a possibility if I was still overseas. The "old" SIM is pre-paid and will not work here (no roaming). But turning iMessage and FaceTime off before leaving a country sounds like an intelligent approach for the future, although I have never seem this problem before (and I have done this type of SIM card swap a lot of times).

As for deregistering, one of the options I've tried was to remove my local number from my AppleID and even without a phone number there I can't still get it to work.

It's really strange, as it works on and off from the phone (never when I really need, always when I test

I will bug Apple Support tomorrow to see if the "engineers" have found a solution to it

Understood.

9:04 pm      Sunday; November 22, 2015

Wow. I did a clean install of 10.11 last night on a new raid array in a MacPro 4,1 last night and I have this same problem. I have tried almost every suggestion on this thread including changing my actual iCloud login (which was a total pain), messing with keychains, deleting and reconfiguring email accounts, resetting the NVRAM, etc... I have not reinstalled the operating system. That's ridiculous in my opinion. Apple support has no clue what I'm talking about when I call. It's pointless. I still cant get iMessage to login with my apple ID. "Enter Apple ID. Sign in with your Apple ID to activate iMessage: An error occurred during authentication."

The ironic thing is that I have another installation of 10.11 on this same machine. When I boot to it, iMessage works fine.

Its a shame. I really used this little app a lot. Very useful.

This worked for me:

Reboot while holding command-option-P-R until you hear a second chime.

Resetting the NVRAM solved the issue for me too! Thank you

First level tech at Apple asked if I was on the latest OSX (I was) and if my System Preferences | Time was set to automatically update and I was in the right time zone.  Then I got bumped to 2nd level.

My fix, while talking to 2nd level tech at Apple involved:

- sign out of iCloud via System Preferences

- renaming ~/Library/Keychains to ~/Library/Keychains.old

- shutdown

- power on

- iMessages | Preferences, and login there (succeeds)

- System Preferences | iCloud & login

FYI, I think I was also logged out of iMessages in my iPhone. I also have an iPad but it was not nearby and was probably still in iMessages.

Hope this helps.

For everyone who has found that all the aforementioned doesn't work, this is the solution. I can't thank you enough for posting this. I haven't been able to use iMessage for over 2 months now.

I too had exactly the same issue. I found that it fixed itself after I signed out of iCloud and quit all the apps that used it and then re-signed in. Then not using keychain but manually I signed into FaceTime first then I was able to sign into iMessage without problem. After that I did a restart and used keychain that time and again all was well.

Hope this helps some of you..!