diff --git a/app/controllers/projects/runner_projects_controller.rb b/app/controllers/projects/runner_projects_controller.rb
index dc1a18f8d4209aa393520e0d59e12ef02af139f3..dc825557928a4bdd9473b5ba376126bbae79e0f9 100644
--- a/app/controllers/projects/runner_projects_controller.rb
+++ b/app/controllers/projects/runner_projects_controller.rb
@@ -6,8 +6,8 @@ class Projects::RunnerProjectsController < Projects::ApplicationController
   def create
     @runner = Ci::Runner.find(params[:runner_project][:runner_id])
 
-    return head(403) if @runner.is_shared? || @runner.locked?
-    return head(403) unless current_user.ci_authorized_runners.include?(@runner)
+    return head(409) if @runner.is_shared? || @runner.locked?
+    return head(409) unless current_user.ci_authorized_runners.include?(@runner)
 
     path = runners_path(project)
     runner_project = @runner.assign_to(project, current_user)