Replication not working with set world scale?

I have just recreated a project and set up my problem again. i am trying to replicate a audio visualizer that is based off of the sounds the players make. I have followed this video (https://www.youtube.com/watch?v=nTCboJrkI8o&t=165s) to make a simple audio visualizer and quickly set up input for the players to start and stop sounds. i set up my rpc and it works for the server but not the clients.