- Set debug=false in system.web section
<compilation defaultLanguage="c#" debug="false" batch="false" targetFramework="4.5">
- Verify custom error mode is RemoteOnly , defaultRedirect is defined and errorpage.html is located in root
<customErrors defaultRedirect="errorpage.html" mode="RemoteOnly" />
- httpErrors defined in system.webServer section of the web.config
<httpErrors existingResponse="PassThrough"/>
- Set 404 page in /config/umbracosettings.config
<errors>
<!-- the id of the page that should be shown if the page is not found -->
<!-- <errorPage culture="default">1</errorPage>-->
<!-- <errorPage culture="en-US">200</errorPage>-->
<error404>1826</error404>
</errors>
- check favico is defined
- check canonical tag exists
var canonicalUrl = Model.Content.UrlWithDomain();
<link rel="canonical" href="@canonicalUrl" />