http://prntscr.com/4yko30

MY RANGE UNIT NOT WORK

WHY??

GAME IS BAD!!!
THIS ON FANTASY 5
THIS NEVER HAPPEN FOR 2 YEAR..

Aaah you're on the losing end of this BR?

http://wiki.battledawn.com/index.php?ti ... Experience, this explains what happened a little bit.
As units fight more they gain more experience giving them extra perks. In this case your enemy had range units with additional range on top of it (so instead of range, think of extra-ranged units). Because of this, his range fires a round before yours does, dealing damage where you do not.
It's some of the more complex mechanics to the game that look confusing at first, but given time to learn is fairly easy to understand.