I tried to solve this problem by myself, but it was not successful.
Please share your wisdom to solve it~
I have iPad, iPhone, MacBook Air and iMac and was using iMessage without any problem.
Then from 1 week before, I couldn't send/receive any message on my iMac suddenly.
At the first time, I thought that it might be a sever problem.
However it seems like it was not.
From last week, though iMessage on other devices are working flawlessly, iMessage on my iMac still does not work.
- SMC / PRAM reset
- Resetting keychain
- Disable / enable my account on iMessage on my iMac
- Using different Apple ID
- adding public DNS server (18.104.22.168, 22.214.171.124)
But it couldn't solve the problem.
Whenever I send a text message, it seems like it was delivered with a sound, then several minutes later, it shows red circle with exclamation mark on right side of the text message, showing there was a problem.
One thing interesting for me is, whenever I disable / enable my account on my iMac, all other devices receive a message that my account is added to the iMac. So, I think it is comunicating with the sever somehow.
Do you have any suggestion?
I hope I don't need to reinstall OS X again....
I've been using iMessage from beta version and now with Messges on Mountain Lion. It WAS working fine though.