diff --git a/app/controllers/main_controller.rb b/app/controllers/main_controller.rb
index da8ad26cb..978ceeb18 100644
--- a/app/controllers/main_controller.rb
+++ b/app/controllers/main_controller.rb
@@ -21,6 +21,7 @@ class MainController < ApplicationController
   end
 
   def index
+    Rails.logger.info("request.referer============#{request.referer}")
     domain_session = params[:_educoder_session]
     if domain_session
       uid_logger("main start  domain_session is #{domain_session}")