Hi, I recently bought a refurbished iMac (the 2011 model) and over the last few days have been trying to set everything up correctly. For some reason I cannot get iMessage to work, and I've tried everything. I am logged in to Messages and it is ready to accept messages at both my iPhone number and my email addresses, however when I try to send a message it does nothing. It just sits there. And after about 3 minutes it'll have a red icon and say "This Message Could Not Be Sent Please Try Again". I've tried several times, and the only times I can get it to go through is when I send one to myself. But even then, only 1 of 10 will go through and it still takes about 3 minutes. Again, every time I send one to someone else it NEVER goes through. I've searched the Apple forums, and these forums as well, unable to find a solution. I tried the many steps suggested here: https://discussions.apple.com/thread/4796390?start=0&tstart=0 to no avail. Any help would be greatly appreciated! Thanks!