Cast to actor Multicast

Hi, I try to create multiplayer game. I have a problem
When I want to kill enemy from server - its okey, but from client - its work only at client.
Replications in enemy blueprint included. When I debug my code, I release that the problem is when I want co cast my weapon blueprint to enemy blueprint - its does not working. But I can cast to third percon character from weapon blueprint. How to make when client kill enemy - server know about it.