When sending a message to the room, the client is duplicated

[wedding-website-dvanh]

when client connect to server: i join it to room with: "client.joinRoom(id);". Then when sending a message to the room, the client is duplicated message receive. I write: "namespace.getRoomOperations(id).sendEvent(listener, new Gson().toJson(result));". Can you help me or give me a sample code to manage and send messages to the room? Thank guys