diff --git a/models/actions/schedule_list.go b/models/actions/schedule_list.go
index b806550b8..ecd2c1121 100644
--- a/models/actions/schedule_list.go
+++ b/models/actions/schedule_list.go
@@ -44,6 +44,9 @@ func (schedules ScheduleList) LoadTriggerUser(ctx context.Context) error {
 			schedule.TriggerUser = user_model.NewActionsUser()
 		} else {
 			schedule.TriggerUser = users[schedule.TriggerUserID]
+			if schedule.TriggerUser == nil {
+				schedule.TriggerUser = user_model.NewGhostUser()
+			}
 		}
 	}
 	return nil
diff --git a/services/actions/notifier_helper.go b/services/actions/notifier_helper.go
index 5d1e2c122..ef37ff87e 100644
--- a/services/actions/notifier_helper.go
+++ b/services/actions/notifier_helper.go
@@ -560,12 +560,9 @@ func DetectAndHandleSchedules(ctx context.Context, repo *repo_model.Repository)
 	}
 
 	// We need a notifyInput to call handleSchedules
-	// Here we use the commit author as the Doer of the notifyInput
-	commitUser, err := user_model.GetUserByEmail(ctx, commit.Author.Email)
-	if err != nil {
-		return fmt.Errorf("get user by email: %w", err)
-	}
-	notifyInput := newNotifyInput(repo, commitUser, webhook_module.HookEventSchedule)
+	// if repo is a mirror, commit author maybe an external user,
+	// so we use action user as the Doer of the notifyInput
+	notifyInput := newNotifyInput(repo, user_model.NewActionsUser(), webhook_module.HookEventSchedule)
 
 	return handleSchedules(ctx, scheduleWorkflows, commit, notifyInput, repo.DefaultBranch)
 }