Often this error is caused by the WebDAV module that try to handle this kind of requests. An easy solution is to remove it from modules and from handlers of the system.webServer
section just inside your web.config file.
Here a configuration example:
<system.webServer>
<modules>
<remove name="WebDAVModule" />
</modules>
<handlers>
<remove name="WebDAV" />
</handlers>
</system.webServer>