diff --git a/adapter/endpoint/manager.go b/adapter/endpoint/manager.go
index 5a633bee..00f8ea3e 100644
--- a/adapter/endpoint/manager.go
+++ b/adapter/endpoint/manager.go
@@ -35,7 +35,6 @@ func NewManager(logger log.ContextLogger, registry adapter.EndpointRegistry) *Ma
 
 func (m *Manager) Start(stage adapter.StartStage) error {
 	m.access.Lock()
-	defer m.access.Unlock()
 	if m.started && m.stage >= stage {
 		panic("already started")
 	}
@@ -43,9 +42,12 @@ func (m *Manager) Start(stage adapter.StartStage) error {
 	m.stage = stage
 	if stage == adapter.StartStateStart {
 		// started with outbound manager
+		m.access.Unlock()
 		return nil
 	}
-	for _, endpoint := range m.endpoints {
+	endpoints := m.endpoints
+	m.access.Unlock()
+	for _, endpoint := range endpoints {
 		err := adapter.LegacyStart(endpoint, stage)
 		if err != nil {
 			return E.Cause(err, stage, " endpoint/", endpoint.Type(), "[", endpoint.Tag(), "]")