<httpErrors errorMode="Custom">
      <clear />
      <remove statusCode="403" subStatusCode="-1" />
      <remove statusCode="404" subStatusCode="-1" />
      <remove statusCode="500" subStatusCode="-1" />

      <error statusCode="403" path="/error-pages/403" responseMode="ExecuteURL" />
      <error statusCode="404" path="/error-pages/404" responseMode="ExecuteURL" />
      <error statusCode="500" path="/error-pages/500" responseMode="ExecuteURL" />
</httpErrors>