FilterStringAsync returning empty string

Hello, i have a chat system where I need to filter every message a player sends. So using FilterStringAsync, that’s what I do. However randomly 2 users talking together cant see each others message as FilterStringAsync returns an empty string, if the users try talking to other people it works fine but when they try talking it returns an empty string.

	local finalMessage = chatService:FilterStringAsync(string.sub(message,1,150), sender, reciever)

	print("Filtered", string.sub(message,1,150), "Result", finalMessage)

Does anyone know why it returns an empty string?