Opponent mitigation

What does it mean when your opponent mitigates your attacks during an attack session? I know that it means I can’t hurt him, but why?
Does this opponent have some kind of stat enhancer or incredible stat gains vs mine? I can’t find this answer anywhere on google, help appreciated.

It is because their defense is at least 14 times more than your strength

Thanks man

other factors would include your weapon's damage rating and your opponent's armor rating

Those have nothing to do with dealing zero damage to an opponent.

ah true. okay