iMessage has stopped working on MacBook Pro I have a 15-inch macbook pro that is mid-2012. The latest version of Mavericks is when the problem started, but it wasn't after the update to it. Just happened one day.

My problem started randomly one day when I tried using iMessage on my mac and all the contacts had turned red. So every time I try to send out a message from my mac, it would immediately say "not delivered."

iMessage works on my iPhone, the only problem is my macbook pro.

I have tried deleting the com.apple.ids.madrid file and that didn't work. I also tried removing my apple ID information from my phone, turning off iMessage on both of the devices, and placing my iPhone 5 in airplane mode for several minutes before turning it on and re-logging in. I can't figure out what the problem is.

I've made sure I'm logged in to my Apple ID, it's nothing like that. I've also tried creating a separate Apple ID just for the purpose of iMessage, but that did no good either.

Please help, it's been weeks and it has become very inconvenient!
Try to use one address (for example e-mail) on all your devises, it worked for me.