<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
        <httpErrors errorMode="Custom" defaultResponseMode="ExecuteURL">
            <remove statusCode="501" subStatusCode="-1" />
            <remove statusCode="500" subStatusCode="-1" />
            <remove statusCode="404" subStatusCode="-1" />
      
            <error statusCode="404" subStatusCode="-1" prefixLanguageFilePath="" path="/404.asp" responseMode="ExecuteURL" />
        </httpErrors>
<rewrite>
    <rules>
        <rule name="HTTP to HTTPS redirect" stopProcessing="true">
            <match url="(.*)" />
            <conditions>
                <add input="{HTTPS}" pattern="off" ignoreCase="true" />
            </conditions>
        <action type="Redirect" redirectType="Permanent" url="https://{HTTP_HOST}/{R:1}" />
        </rule>
    </rules>
</rewrite>
        <staticContent>
            <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="7.00:00:00" />
        </staticContent>
    </system.webServer>
    <system.web>
        <customErrors defaultRedirect="/404.asp" mode="RemoteOnly" />
    </system.web>
</configuration>

buyrun kendinze göre düzenlerseniz çözebilirsiniz. </httpErrors> sonra gelen yönlendirmedir. Bunun dışında bunu hosting firmanızda yapar Plesk panel barındırma ayarlarında var.