Отворете web.config и намерете <system.webServer>
В него въведете
<rewrite>
<rules>
<clear />
<rule name="Redirect to https" stopProcessing="true">
<match url=".*" />
<conditions>
<add input="{HTTPS}" pattern="off" ignoreCase="true" />
</conditions>
<action type="Redirect" url= "https://{HTTP_HOST}{REQUEST_URI}" redirectType="Permanent" appendQueryString="false" />
</rule>
</rules>
</rewrite>