My iMessage is offline, how do I turn it back on?

[iMore Question]

I don't receive any iMessages anymore on my computer. It's working on my iPad and iPhone, but is "offline" on the mac.

 

[bones467]

If you click the iMessage icon, go the messages menu at the top of the screen, preferences/accounts you should be able to log back in there. Hope this helps anything else just ask!

 

[photodr11]

I am having problems with all of my contacts showing up at "offline", on both of my macs.. Only after the most recent update, maybe a month or 2. I am signed in and says I am online, has anyone heard of this recently? Or know how to fix it? Hope all is well.