I just know of Apple Mail use the menu time 'Window' and in top down select 'Connection Doctor'! If you print it out you see where you screwed up! When I setup my GMAIl servers I used the support document GMail Server setup and went into my Gail setup on web to allow a connection to the device too!
The Android phone users are jealous of iMessages and green bubble in it while it is blue when ad Android or MMS message is received! I call it envy by those very Android users! ;)
It's called a walled garden by those consumers with lesser smart phone think iMessage should be on Android too becloud ause kids see the iPhone as status symbol! Also andriod users are jealous of iPhones green button in iMessage and from MMS if blue! I call that bad blood!