Q: The registering device does not have appropriate credentials.

HI,

Have you seen this article ?

http://support.apple.com/kb/ht5419

2:34 PM      Friday; July 27, 2012

Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"

  iMac 2.5Ghz 5i 2011 (Lion 10.7.2)
 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb (Snow Leopard 10.6.8)
 Mac OS X (10.6.8),

"Limit the Logs to the Bits above Binary Images."  No, Seriously

Ralph: that support document does not apply to this problem. The error messages are different. No such dialog appears.

Interesting that this apparently just started happening a few days ago.

I just starting having the same problem this morning, Does your dialog box look similar to this:

just to add my iPhone iMessages are working fine.

John

I found a solution for this:

Go to Activity Monitor

Find and Quit IMagent

I can not take credit for this ,I found it on an another thread.

https://discussions.apple.com/thread/5041282

John

Hi Larry,

You are right and so am I as this thread start date is over a year old and deals with a different problem.

(well a similar problem of non registration but a different issue regarding it.)

Edit.

As Deadcowboy has found Ofir Gal was the first to post the current issue fix

https://discussions.apple.com/message/22572970#22572970

9:15 PM      Saturday; August 3, 2013

  iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.4)
 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb (Snow Leopard 10.6.8)
 Mac OS X (10.6.8),
 Couple of iPhones and an iPad

"Limit the Logs to the Bits above Binary Images."  No, Seriously

Message was edited by: Ralph Johns (UK)

Thanks Deadcowboy. Quitting IMagent worked! And it is the only thing out of 20 that did.

See also http://support.apple.com/kb/TS3970

8:37 PM      Wednesday; August 21, 2013

  iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.4)
 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb (Snow Leopard 10.6.8)
 Mac OS X (10.6.8),
 Couple of iPhones and an iPad

"Limit the Logs to the Bits above Binary Images."  No, Seriously

This worked. Thanks Deadcowboy