diff --git a/app/controllers/import_zendesk_controller.rb b/app/controllers/import_zendesk_controller.rb
index 7d8af5d1c..a4324102e 100644
--- a/app/controllers/import_zendesk_controller.rb
+++ b/app/controllers/import_zendesk_controller.rb
@@ -23,7 +23,7 @@ class ImportZendeskController < ApplicationController
       'Connection refused'                                        => 'Connection refused!',
     }
 
-    response = UserAgent.request( params[:url] )
+    response = UserAgent.request(params[:url])
 
     if !response.success?
       message_human = ''
@@ -40,6 +40,15 @@ class ImportZendeskController < ApplicationController
       return
     end
 
+    # since 2016-10-15 a redirect to a signup page has been implemented
+    if response.body =~ /(Take it for a risk-free|Take it for a risk-free)/i
+      render json: {
+        result: 'invalid',
+        message_human: 'Hostname not found!',
+      }
+      return
+    end
+
     Setting.set('import_zendesk_endpoint', "#{params[:url]}api/v2")
 
     render json: {