i have successfully added a custom 404 page. what I want to do is to create another custom error page that is displayed when there is any error other than 404. e.g. 500, 403 etc.
this is what I have right now in webconfig
<httpErrors errorMode="Custom" existingResponse="Replace">
<remove statusCode="404" subStatusCode="-1" />
<error statusCode="404" path="/404.aspx" responseMode="ExecuteURL"/>
</httpErrors>
Oh, my. I cannot believe I could not find a proper answer for this simple question! Nevertheless, after 2 hours of reading the docs and debugging, I found it.
<httpErrors errorMode="Custom" existingResponse="Auto" defaultResponseMode="ExecuteURL" defaultPath="/App/Error"> <!-- Do not include ~, this was my issue all long -->
<clear/> <!-- so that IIS provided error pages are skipped -->
<!-- add those which you like to provide a view of yours -->
<error path="/App/Http404" responseMode="ExecuteURL" statusCode="404"/>
<error path="/App/Http503" responseMode="ExecuteURL" statusCode="503"/>
</httpErrors>
Beaware that <httpErrors>
configures IIS, while <customErrors>
configures ASP.NET and some older versions of IIS (<=6?).