How to control the use of friendly error messages in Internet Explorer
By default, web servers return 3-digit numeric error codes and terse “Reason” phrases when an error occurs. (For more about these codes and reason phrases, see HTTP errors.) Only if they are customized do they elaborate with more informative explanation about the error. To give users more information about errors when the server only returns such brief responses, Internet Explorer provides its own “friendly error messages” when the response from the server is shorter than a threshold (512 bytes for most responses). While often useful, such friendly error messages can occasionally hide more specific information provided by the server, so you might want to disable them.
To control whether Internet Explorer uses “friendly error messages”:
- Go to the Internet Options control panel
- On the “Advanced” tab, scroll to the “Browsing” settings
- Towards the end of those settings, set the “Show friendly HTTP error messages” as you wish.
- Click the “OK” button.
The thresholds are specified by registry values
Microsoft Knowledge Base article 218155: “Description of Hypertext Transport Protocol Error Messages”
“This article describes the use of friendly Hypertext Transport Protocol (HTTP)-status error messages.”
Microsoft Knowledge Base article 294807: “HOW TO: Turn Off the Internet Explorer 5.x and 6.x “Show Friendly HTTP Error Messages” Feature on the Server Side”