"# is not registered with iMessage" error Let me clearly establish that I am not trying to send a sms to a non-iPhone user. On my OS x Mountain Lion macbook pro I was sending iMessages from the Messages application just fine until all of a sudden my Messages application is claiming that all of my iPhone-using contacts are not actually iPhone-using contacts. On my iPhone my messages are being sent and received just fine, it is the computer I am typing this on that has the issue. 

I floated through the apple forums and saw a few suggestions - signing in and out in Messages(tried and could sign in fine but my application still thinks it's everyone else with the problem), checking to see that my macbook still knows its own serial number (it does), restarting my computer (no effect), and changing wifi networks (no effect). 

Has anyone else had this issue with their Messages app on their apple computing device and, if you have, how were you able to fix it? Did it vanish at random as suddenly as it appeared or are there some missing settings that I couldn't think of? 

Thank you.
I've got several contacts that are offline in iMessage and they have gone through all the troubleshooting steps.

Everything points to this being a service disruption as opposed to something you or your contact has done wrong.



http://www.apple.com/support/systemstatus/