diff --git a/wshandler/wshandler.go b/wshandler/wshandler.go
index b4f4daf..fc4986e 100644
--- a/wshandler/wshandler.go
+++ b/wshandler/wshandler.go
@@ -431,7 +431,8 @@ func (sh *subhandler) mainLoop(ctx context.Context) {
 					if conn != nil {
 						if room := findRoom(roomName, false); room != nil {
 							if conn.popRoom(room.out(conn)) == 0 {
-								conn.WriteControl(websocket.CloseMessage, []byte("normal"), time.Time{})
+								closeMsg := websocket.FormatCloseMessage(websocket.CloseNormalClosure, "")
+								conn.WriteControl(websocket.CloseMessage, closeMsg, time.Time{})
 							}
 							break
 						}
@@ -491,7 +492,8 @@ func (sh *subhandler) mainLoop(ctx context.Context) {
 					if conn != nil {
 						if room := findRoom(roomName, false); room != nil {
 							if conn.popRoom(room.out(conn)) == 0 {
-								conn.WriteControl(websocket.CloseMessage, []byte("normal"), time.Time{})
+								closeMsg := websocket.FormatCloseMessage(websocket.CloseNormalClosure, "")
+								conn.WriteControl(websocket.CloseMessage, closeMsg, time.Time{})
 							}
 						}
 					}