I had a case of an IIS site that had link to a local ODT file (Office Document Text, used by Open office and star office).
Anyone clicking on this link was getting a 404 error, file not found. I made sure the url is correct, the file exists where it is supposed to be, etc..
After some investigation, it turned out that this file did not have its MIME type defined in IIS. As a result IIS was not serving an unknown MIME type: https://support.microsoft.com/en-us/help/326965/iis-6-0-does-not-serve-unknown-mime-types
To fix this issue, simply add the MIME type to the designated site
- Open IIS Manager and navigate to the level you want to manage. For information about opening IIS Manager, see Open IIS Manager (IIS 7). For information about navigating to locations in the UI, see Navigation in IIS Manager (IIS 7).
- In Features View, double-click MIME Types.
- In the Actions pane, click Add.
- In the Add MIME Type dialog box, type a file name extension in the File name extension text box. For example, type .xyz.
- Type a MIME type in the MIME type text box. For example, type application/octet-stream.
- Click OK.
Ref: https://technet.microsoft.com/en-us/library/cc725608%28v=ws.10%29.aspx
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