How to properly setup network replication?

Hey guys,
I have a problem with very simple network replication. It’s the first time I lay hands on that but Iam not even able to get the simplest things accomplished… Sooo… What I wanted for test purposes is just to spawn a sphere in the level that is being replicated to the clients.

The code for the spawning is that simple here:

It simply spawns a blueprint class that only contains a sphere component (that blueprint class has “replicates” checked). The event is called upon BeginPlay:

It works for the server, so that the sphere is spawned and also replicated to the client. However, the client side does not work. That is how I set it up:

The Client is supposed to call an event that is being run on the server and essentially calls the same function as shown above. Only with a different location so that I can distinguish both visually.
Well, but the client path does not work. Neither client nor server see the sphere that should be spawned there…

Can you help me to find where I went wrong?

Best wishes,