If iMessage on Mac not working is something that is dogging you, give these fixes a shot: Reboot Mac Still, it's worth troubleshooting, as one of the solutions below likely solves any iMessage woes.
Because each Mac has different settings and unique app settings, there's not a single answer that works for everyone. Why won't iMessage work on my Mac? It's a simple question with several possible solutions. Try free How to fix iMessage not working on Mac