diff --git a/internal/agent/controller/app/server.go b/internal/agent/controller/app/server.go
index 2da9395..248ad72 100644
--- a/internal/agent/controller/app/server.go
+++ b/internal/agent/controller/app/server.go
@@ -35,12 +35,15 @@ type Server struct {
 }
 
 func (s *Server) Start(ctx context.Context, addr string) (err error) {
-	if s.server != nil {
+	if s.Running() {
 		if err := s.Stop(); err != nil {
 			return errors.WithStack(err)
 		}
 	}
 
+	s.serverMutex.Lock()
+	defer s.serverMutex.Unlock()
+
 	router := chi.NewRouter()
 
 	router.Use(middleware.Logger)
@@ -85,9 +88,7 @@ func (s *Server) Start(ctx context.Context, addr string) (err error) {
 		}
 	}()
 
-	s.serverMutex.Lock()
 	s.server = server
-	s.serverMutex.Unlock()
 
 	return nil
 }
@@ -100,20 +101,25 @@ func (s *Server) Running() bool {
 }
 
 func (s *Server) Stop() error {
+	if !s.Running() {
+		return nil
+	}
+
+	s.serverMutex.Lock()
+	defer s.serverMutex.Unlock()
+
 	if s.server == nil {
 		return nil
 	}
 
-	defer func() {
-		s.serverMutex.Lock()
-		s.server = nil
-		s.serverMutex.Unlock()
-	}()
-
 	if err := s.server.Close(); err != nil {
+		s.server = nil
+
 		return errors.WithStack(err)
 	}
 
+	s.server = nil
+
 	return nil
 }