Symptoms
Webmail gives a Page/Directory not found (404) error
Cause
On certain versions of IIS (for example the Windows 2003 version) Active Server Pages (ASP) can be disabled.
Resolution
Enable Active Server Pages in IIS to enable Webmail to run.
Detail
Open the Internet Information Services (IIS) Manager, expand your computer and click on Web Service Extensions. Check Active Server Pages are allowed. If, select them and click enable.