diff --git a/app/controllers/trainings_controller.rb b/app/controllers/trainings_controller.rb
index f041e958..e5ef1529 100644
--- a/app/controllers/trainings_controller.rb
+++ b/app/controllers/trainings_controller.rb
@@ -6,7 +6,7 @@ class TrainingsController < ApplicationController
   skip_before_filter :check_if_login_required
   skip_before_filter :verify_signature, except: [:auth, :auth_callback, :pay_callback]
 
-  ROOT_URL = ENV["wechat_url"] || "#{Setting.protocol}://engineer.educoder.net"
+  ROOT_URL = ENV["wechat_url"] || "#{Setting.protocol}://#{Setting.host_name}"
 
   before_filter :authenticate, except: [:auth, :auth_callback, :pay_callback]