My code is a bit of a mess, so here is a watered down version:
This is designed to mute players when they join, its bunded in with an admin system I am creating.
local csr = require(game:GetService("ServerScriptService"):WaitForChild("ChatServiceRunner").ChatService)
--/Player join functions and stuff, the player is defied as 'p'
local channel = csr:GetChannel("ALL")
channel:MuteSpeaker(p.Name)
Error message
ServerScriptService.ChatServiceRunner.ChatChannel:177: Speaker "Claym1x" does not exist! - Server - ChatChannel:177
17:18:23.041 Stack Begin - Studio
17:18:23.042 Script 'ServerScriptService.ChatServiceRunner.ChatChannel', Line 177 - function
Bunch of callbacks here..
I have ran code similar to this not too long ago, and it worked perfectly fine, so I am not sure what gives here. I have tried to make the username lowercase, but it just returns the same error.
if you see an issue, or need more of the script’s code, let me know. Cheers!