after El Capitan FaceTime not working

Same things happened to me!!! it's still working on iPhone though.

This could be a complicated problem to solve, as there are many possible causes for it. Test after taking each of the following steps that you haven't already tried. Back up all data before making any changes.

Before proceeding, test on another network, if possible. That could be a public Wi-Fi hotspot, if your computer is portable, or a cellular network if you have a mobile device that can share its Internet connection. If you find that iMessage works on the other network, the problem is in your network or at your ISP, not in your computer.

Step 1

Check the status of the service. If the service is down, wait for it to come back up. There may be a localized outage, even if the status indicator is green.

Step 2

Sign out of iMessage and FaceTime on all your Apple devices. Log out and log back in. Try again to sign in.

Step 3

Restart your router and your broadband device, if they're separate. You may have to skip this step if you don't control those devices.

Step 4

Follow these instructions to display the machine's serial number. If the number is missing or invalid according to this web form, take the machine to an Apple Store or other authorized service center to have the problem corrected.

Step 5

Take the steps suggested in this support article. If you don't understand some of the steps or can't carry them out, ask for guidance.

Step 6

From the menu bar, select

 ▹ System Preferences... ▹ Network

If the preference pane is locked, click the lock icon in the lower left corner and enter your password to unlock it. Then click the Advanced button and select the Proxies tab. If the box marked SOCKS Proxy is checked, uncheck it. You don’t need to change any other settings in the window. Click OK and then Apply. Test.

The result may be that you can't connect to the Internet at all. Revert the change if that happens, or if iMessage still doesn't work. Remember that you must Apply any changes you make in the preference pane before they take effect.

Step 7

Select from the menu bar

 ▹ System Preferences… ▹ Flash Player ▹ Storage

and click

Block all sites from storing information on this computer

Close the preference pane.

Step 8

Make sure you know the ID and password you use with iMessage. Launch the Keychain Access application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad and start typing the name.

Use the search box in the toolbar of the Keychain Access window to find and delete all items with "iMessage" or "com.apple.idms" in the name. Log out and log back in.

Step 9

Enable guest logins* and log in as Guest. Don't use the Safari-only “Guest User” login created by “Find My Mac.”

While logged in as Guest, you won’t have access to any of your personal files or settings. Applications will behave as if you were running them for the first time. Don’t be alarmed by this; it’s normal. If you need any passwords or other personal data in order to complete the test, memorize, print, or write them down before you begin.

Test while logged in as Guest. After testing, log out of the guest account and, in your own account, disable it if you wish. Any files you created in the guest account will be deleted automatically when you log out of it.

*Note: If you’ve activated “Find My Mac” or FileVault, then you can’t enable the Guest account. The “Guest User” login created by “Find My Mac” is not the same. Create a new account in which to test, and delete it, including its home folder, after testing.

If iMessage worked in the guest account, stop here and post your results.

Step 10

Start up in safe mode and log in to the account with the problem.

Note: If FileVault is enabled in OS X 10.9 or earlier, or if a firmware password is set, or if the startup volume is a Fusion Drive or a software RAID, you can’t do this. Ask for further instructions.

Safe mode is much slower to start and run than normal, with limited graphics performance, and some things won’t work at all, including sound outputand Wi-Fi on certain models. The next normal startup may also be somewhat slow.

The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.

Test while in safe mode. After testing, restart as usual (i.e., not in safe mode) and test again.

If iMessage worked in safe mode, but still doesn't work when you restart in "normal" mode, stop here and post your results.

Step 11

Triple-click anywhere in the line below on this page to select it:

/Library/Preferences/com.apple.apsd.plist

Right-click or control-click the highlighted line and select

Services ▹ Reveal in Finder (or just Reveal)

from the contextual menu.* A folder should open with an item selected. Move the selected item to the Trash. You may be prompted for your administrator login password. Restart the computer and empty the Trash.

*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination command-C. In the Finder, select

Go ▹ Go to Folder...

from the menu bar and paste into the box that opens by pressing command-V. You may not see what you pasted because a line break is included. Press return.

Step 12

Reset theNVRAM.

Step 13

Reset the System Management Controller (SMC).

Step 14

Reinstall OS X.

Step 15

If none of the above steps resolves the issue, make a "Genius" appointment at an Apple Store, or contact Apple Support. When you set up a support call, select "Apple ID" as the product you need help with, not the hardware model. That way, if you're not under AppleCare, you may be able to talk your way out of being charged for the call.

/Library/Preferences/com.apple.apsd.plist did it for me.

Safe Mode had got me back into Messages but not FaceTime.

I'd been working from a different checklist before I found Linc's [as always] excellent post, so had worked through things in a different order…

• Firewall/router checks & reboots, etc - though as my iCloud login was working fine for everything else & my Firewall is easy to inspect for what is falling afoul of it, this wasn't my prime suspect.
• Sign out of everything, iCloud, App Store, iTunes...
• NVRAM
• Safe Mode
• Dance round in ever-decreasing circles, applying finer & finer points of black-belt Google-Fu...

Then I found Linc's post & the plist paragraph - worked first time.

Many thanks.

Thanks, Linc, this is great stuff. I always appreciate your thorough replies (though I am mostly a "lurker" on these forums.)

Anyway...I have tried everything on you list above and I still can't log into to iCloud (via the "iCloud" preference pane, or via the App Store, or via an occasional Messages pop-up dialog.

I have even had my hardware checked out an an authorized service center and it passed 100%.

I can create new account with new Apple IDs, I just can't log in via my old account using my existing Apple ID.

I have done a lot of googling and many folks swear by the "delete plist" cure but that is not working for me.

FWIW, I upgraded from 10.10.5 directly to 10.11.2. I can't access the App Store or log in to iCloud services of any kind. I have it woring fine on another Mac and on an iPhone and on an iPad. On my "problem Mac" a bunch of processes are peggged at 100% and the fans vlow like crazy. The Mac is kind kind useless because of this, even when I am not using iCLoud features.

Can ANYONE suggest anything else to try?

apple removed my last comment because it wasn't technical enough....

whatever!

I have checked and unchecked and rechecked everything that can be checked.

I have re-installed el capitan per apple (un)care

restarted computer to point if i hear the sound of a restarting computer i will break out in tears.... i have been doing this for 12 hours now...

nothing has worked.

apple (un)care has not helped at all...

this happens with every update!!!!

I am beyond frustrated!!!

I don't know what else to do, apple hasn't helped.... honestly I think that this is a glitch that they caused!

I need this fixed and they need to help and not make it worse and ignore the issue!