ASP.NET IIS Firefox authentication required problem

Today, I had problem with running my asp.net project while using Firefox. It asked me to enter username and password to see the page. However, I tried all the passwords and none of them worked. This problem never occurred before, so I googled and finally found the solution.

1. Enter about:config at firefox address bar. (You will see warning message indicating that these are advanced settings that may affect the browser security and stability)
   
2. Click "I'll be care, I promise" button
3. Search network.automatic-ntlm-auth.trusted-uris at filter. (Only one entry will be appear)
4. Double click the entry and type localhost.
5. Save it and reload your web page then DONE!
   

Here's the original link from ASP.net forum.