iMessage is not working on my mac.

I have the exact same problem. It used to log in fine, and out of no where it doesnt sign in. Can someone help me and weffa??

I kept getting an error message the last couple of days (since the latest flash update) that the imessage could not be sent. So, I tried the solution above, uninstalled flash from my mbp running osx 10.9.2, and then went back into imessage. Message sent immediately. Thanks for the tip!

don't know why, but that worked!

this doesn't fix my problem... any other suggestion on how to fix this?

This worked for me too! Thank you. I just changed the preferences for Adobe Flash Player Storage. Odd that it would affect iMessage...

I just did this and it solved my problem! Thank you!

How do you delete all local data?

worked perfectly.

Wow....I could have never figured that out! Thanks

Been having a problem for two days now, your solution is the only one that worked for me.

Thank you!

thanks! this worked for me

Amazing that this issue is still around after two years. Thanks

This WORKED - I tried all sorts of things.

My problem was fixed when I went to

messages > preferences > accounts

and realized I was logged out for some reason.

Thanks!

You need to connect/link/sync Iphone and mac. In iphone go to settings > messages>send& receive and add apple ID email address/addresses. In my case I have the icloud email and also my yahoo email which is what I used to originally create my Apple ID. Once I did that my mac asked me if I wanted to connect my phone number to my computer. I accepted and it is all working now.

Oh! one other step I forgot, I removed my computer from "devices being used" in my iphone.

-- settings> icloud> tapped on my ID/user name> Devices> and removed my computer.

I'm not sure if that made a difference but all is working now!