The server has encountered an error processing registration. Please try again later"

Back up all data.

Take the steps suggested in this support article:

FaceTime, Game Center, Messages: "There was an error processing registration" when signing in

The time zone must be correct for your location.

Make sure you know your ID (an email address) and password. The password should be in your keychain, which you access in the Keychain Access application.

Sign out of iMessage:

Messages ▹ Preferences ▹ Accounts ▹ Sign out

Then sign back in with your verified credentials.

I've been trying to get an answer to this problem for MONTHS. I upgraded both my iMac and my MacBook Pro to Mountain Lion, and ever since, FaceTime and iMessage stopped working. I got the "Server encountered an error . . ." So, I called Apple "support" and they claimed they haven't heard of this issue. I said I find it hard to believe since it's apparently a huge problem for tons of users and is all over the Apple forums. After spending an hour on the phone with "support", they said they had to pass i on to a senior engineer and they'd call me back within 2 days with an answer. After waiting a week, I decided to go to the place where I should have gone before, the place where all questions can be answered, even those too advanced for Apple, that place . . . YouTube.

Fixing the time issue didn't work for me, nor did any other solution that has been posted on the boards. Yet after watching a 1:24 video on YouTube, both FaceTime and iMessage now work for me.

Here's the solution which WILL work.

1. You do need to first make sure your date/time settings are correct and set to adjust automatically. But doing just this step will not fix the problem.
2. Open Finder, click on "Go" at the top menu, then select "Go To Folder"
3. Type in /etc and hit enter
4. You'll see a file called "hosts". Drag that file to your desktop.
5. Right click on that file and open with Text Edit
6. Select all the text in that file, delete it and replace it with the text below, exactly as it is below. Then save the new hosts file (just exiting will save it). And then drag that new hosts file back into the /etc folder to replace the old one. After that, your FaceTime and iMessage will work, no thanks to Apple.

##

# Host Database

#

# localhost is used to configure the loopback interface

# when the system is booting. Do not change this entry.

##

127.0.0.1 localhost

255.255.255.255 broadcasthost

::1 localhost

fe80::1%lo0 localhost

Thank you toddwest24. I just upgraded to ML specifically for iMessage but was having the errors signing in and/or registering my account. Used your method, went straight through the sign in process.

I have this same problem however I tried the suggested solution but it didnt work.

Thanks Toddwest24, worked first time, apple support and the apple shop could not fix, I have been working on this fopr 3 weeks. Mate well done 🙂

I had this problem. Going into the Console utility revealed odd errors from the imagent process. Went into Activity Monitor and stopped that process. It regenerated a replacement process. Problem gone after that.

Sad to say.. same issue. Tried Toddwest24's fix - didn't work. See a few errors in console but not sophisticated enuf to know what it means 😕 Date is on Auto, all other suggestions tried. PS.. It was working until yesterday, but I have not loaded anything, downloaded anything or changed any other settings. Suggestions appreciated!

Ah, killing imagent worked. The time, timezone, firewall, hosts file, etc were all fine. iMessage broke yesterday (2013-07-31) around 14:00 PDT and had been working fine until then. Very odd. There were no imagent errors logged anywhere however. Theoretically a reboot should also fix this since that would give you a new imagent. I did not reboot but I think other people have tried rebooting with no luck though. Again, odd.

Here are more detailed instructions on how to kill imagent.

Run Activity Monitor (Spotlight for "activity monitor" and run). Display the process list with Window ➔ Activity Monitor (or ⌘1). Pull down the filter list and select My Processes. Enter im in the search box. Click on imagent:

Click on Quit Process. Click on Quit.

Then reactivate your iMessage account in Messages. That worked for me.

Thx...That's work!!