Create a web.config file with the code below and place it into root.
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<directoryBrowse enabled="false" />
<defaultDocument>
<files>
<clear />
<add value="index.html" />
<add value="index.htm" />
<add value="default.html" />
<add value="default.htm" />
<add value="index.php" />
<add value="index.py" />
<add value="index.pl" />
<add value="default.asp" />
<add value="default.aspx" />
<add value="index.asp" />
<add value="index.aspx" />
<add value="holding.html" />
</files>
</defaultDocument>
<httpErrors errorMode="Detailed" />
</system.webServer>
</configuration>