diff --git a/samples/IdentitySample.Mvc/web.config b/samples/IdentitySample.Mvc/web.config
index 7a210ad15b..71ebc78e72 100644
--- a/samples/IdentitySample.Mvc/web.config
+++ b/samples/IdentitySample.Mvc/web.config
@@ -9,7 +9,7 @@
   <appSettings>
     <!-- This will turn on detailed errors when deployed to remote servers -->
     <!-- This setting is not recommended for production -->
-    <add key="K_DETAILED_ERRORS" value="true" />
+    <add key="ASPNET_DETAILED_ERRORS" value="true" />
   </appSettings>
 
 </configuration>
\ No newline at end of file