diff --git a/protocol/wireguard/endpoint_warp.go b/protocol/wireguard/endpoint_warp.go
index 9773cd01..24e129cc 100644
--- a/protocol/wireguard/endpoint_warp.go
+++ b/protocol/wireguard/endpoint_warp.go
@@ -185,31 +185,28 @@ func (w *WARPEndpoint) Start(stage adapter.StartStage) error {
 }
 
 func (w *WARPEndpoint) Close() error {
-	if err := w.isEndpointInitialized(); err != nil {
-		return err
+	if ok := w.isEndpointInitialized(); !ok {
+		return E.New("endpoint not initialized")
 	}
 	return w.endpoint.Close()
 }
 
 func (w *WARPEndpoint) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
-	if err := w.isEndpointInitialized(); err != nil {
-		return nil, err
+	if ok := w.isEndpointInitialized(); !ok {
+		return nil, E.New("endpoint not initialized")
 	}
 	return w.endpoint.DialContext(ctx, network, destination)
 }
 
 func (w *WARPEndpoint) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
-	if err := w.isEndpointInitialized(); err != nil {
-		return nil, err
+	if ok := w.isEndpointInitialized(); !ok {
+		return nil, E.New("endpoint not initialized")
 	}
 	return w.endpoint.ListenPacket(ctx, destination)
 }
 
-func (w *WARPEndpoint) isEndpointInitialized() error {
+func (w *WARPEndpoint) isEndpointInitialized() bool {
 	w.mtx.Lock()
 	defer w.mtx.Unlock()
-	if w.endpoint == nil {
-		return E.New("endpoint not initialized")
-	}
-	return nil
+	return w.endpoint != nil
 }