Attacking question


I have been play this game on and off for a few years. But this is the first time I have ever ran into this issue.

I do all the right things before attacking. I spy, I use the simulator to see what my outcome will be, but each time I attack with more then enough troops or a Nuke attack on a city all my troops get killed.

I am getting frustrated I just lost 685 hops 150 horses, 8 catapults, 150 slingers. The simulator say I should have left over troops.

I am taking on only 397 swards, 44 slingers, 13 archers, and 137 divine envoy with a wall at lv 10 temple at lv 3

What am I missing?
Anybody know what would cause all my troops to die and nothing happen to the city, not even a dent?