Why Can't I Get 'RBXEmoteCommand'?

I am trying to get RBXEmoteCommand to change the /e to /f

local ChatService = game:GetService("TextChatService")

ChatService.MessageReceived:Connect(function(msg:TextChatMessage)
    local TextChatCommands = msg:WaitForChild("TextChatCommands")
    local RBXEmoteCommand = TextChatCommands:WaitForChild("RBXEmoteCommand")
    RBXEmoteCommand.SecondaryAlias = "/f"
end)

The error show this:

Infinite yield possible on 'Instance:WaitForChild("TextChatCommands")'

Sorry if this question is unclear!