imessage error from mba to iphone5s
this problem has been bugging me for awhile. I can't send imessage from my mba (mavericks) to iphone5s (8.1.2). I signed in with 2 separate apple id's. It used to work but stopped a couple of months ago. When I tried to send imessage from my mac to iphone, it kept saying the account or phone number is not registered with imessage. but they are. I can send imessage from my iphone to ipad and vice versa, with the apple id that my mba says not registered with imessage.
I tried signing in and signing out on all devices. I even deleted the library file that stores apple id info. but the problem persists. how can I fix this?
MacBook Air, OS X Mavericks (10.9.5)