RPCS doesn't work

I want A character can change other B character(“Flagholder”)'s variable(“Command”),but it‘s always work on server except my client,I don’t know why…
the functions look like this:

B character’s head file

53209-1.jpg

definition:

In my A’s Blueprints that is Inherited from A character,when evet happens ,this functions will be called.

I don’t know why it’s doesn’t work in blueprint,But I bind “Action” in C++,It’s fixed…