Most of the time I use 1.8, but I started using 1.15 recently. To register a plugin channel in 1.8, you would just pass a parameter into the registerChannel method. In 1.13, a good amount of stuff was switched over to namespaces. If I register my channels in my spigot plugin without the namespacekey) then it throws an exception, but the same channel has to be registered in bungee as well. Bungee Main Class: Code (Text): BungeeCord.getInstance().registerChannel("namespace:execute"); Spigot Main Class: Code (Text): Bukkit.getMessenger().registerIncomingPluginChannel(this, "namespace:execute", new PluginMessager()); When I try to send data through the channel with this method: Code (Text): server.sendData("execute", stream.toByteArray()); nothing happens. I'm not sure what I am doing wrong with this.