I've been recently trying to fix an issues with Messages.app. My iPhone sends/receives all of the messages fine, on my Mac Messages.app will display these messages if the Mac is switched on.
However, if I leave my Mac off then the messages do not appear in Messages.app which is incredibly frustrating.
I have tried signing in and out on both devices, but nothing changes. Forwarded SMS is also having this issue.
I'm currently running OSX 10.10.3 and iOS 8.3 12F70