[networking] Client call to Server RPC not being called?

I’m trying to use a client HUD to fire a “Run on Server - Reliable” event on the server, which does some server-side calculation, then fires a “run on client” code.
However, when I press the button, the event doesn’t actually fire. I can’t seem to understand the reason for this, as my understanding was that if the even is set to be “Run on server” it should be doing exactly what I’m expecting.

Moreover, what I’d really like to do is something like this:

  • Clients start up to a hud and on a button press, execute code on the server to generate things like starting location and HP and such. At this point the PlayerCharacter is None. When the server is done, it fires an RPC back into the calling client with the starting location and such
  • Clients then Spawn Actor for their PlayerCharacter and take possession of it. My understanding is that by default the StarterContent MyCharacter blueprint is replicated and such, so it should create properly across all clients.
    -the rest is firing objects (spawning them on the server) and such

What piece of the logic have I messed up here???

the hud exists only one the Client side