All of my usual contacts that I could send messages on my MacBook Pro stopped working all of a sudden. They are all in red. I ran disk utility, rebooted, and even rebooted my phone, but nothing is making a difference. I can't even send a message to myself!
Any suggestions?
I have not yet updated to the newest version of OS because I'm tired of being a beta-tester.
I can only send messages on my iPhone, not on my computer.
Any suggestions greatly appreciated!
MacBook
Pro, OS X Yosemite (10.10.5)