diff --git a/api/auth/center.go b/api/auth/center.go
index aa3a501..0d968af 100644
--- a/api/auth/center.go
+++ b/api/auth/center.go
@@ -44,6 +44,8 @@ type (
 	prs int
 )
 
+var ErrNoAuthorizationHeader = errors.New("no authorization header")
+
 func (p prs) Read(_ []byte) (n int, err error) {
 	panic("implement me")
 }
@@ -70,7 +72,7 @@ func (c *center) Authenticate(r *http.Request) (*token.BearerToken, error) {
 
 	authHeaderField := r.Header["Authorization"]
 	if len(authHeaderField) != 1 {
-		return nil, nil
+		return nil, ErrNoAuthorizationHeader
 	}
 
 	sms1 := c.reg.getSubmatches(authHeaderField[0])
diff --git a/api/user-auth.go b/api/user-auth.go
index 0d8f5a0..df150a4 100644
--- a/api/user-auth.go
+++ b/api/user-auth.go
@@ -19,17 +19,17 @@ var BearerTokenKey = KeyWrapper("__context_bearer_token_key")
 func AttachUserAuth(router *mux.Router, center auth.Center, log *zap.Logger) {
 	router.Use(func(h http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			var ctx context.Context
 			token, err := center.Authenticate(r)
 			if err != nil {
-				log.Error("failed to pass authentication", zap.Error(err))
-				WriteErrorResponse(r.Context(), w, GetAPIError(ErrAccessDenied), r.URL)
-				return
-			}
-
-			var ctx context.Context
-			if token == nil {
-				log.Info("couldn't receive bearer token, switch to use neofs-key")
-				ctx = r.Context()
+				if err == auth.ErrNoAuthorizationHeader {
+					log.Debug("couldn't receive bearer token, using neofs-key")
+					ctx = r.Context()
+				} else {
+					log.Error("failed to pass authentication", zap.Error(err))
+					WriteErrorResponse(r.Context(), w, GetAPIError(ErrAccessDenied), r.URL)
+					return
+				}
 			} else {
 				ctx = context.WithValue(r.Context(), BearerTokenKey, token)
 			}