IIS: 404 - File or directory not found

You receive following error about a file on IIS webserver although the file is there.

Error

Server Error: 404 - File or directory not found.

Cause

There are a lot of different reasons for this error, but maybe the error occurs because the file extension you request are denied in the IIS configuration (Request Filtering).

Solution

• Open IIS Manager and select the level for which you want to configure request filter.
• In Features View, double-click Request Filtering:

• Select the File Name Extensions tab.
• In the Actions pane, click either Allow File Name Extension.
• Type the file name extension in the box, and then click OK.