Currently, this works (returns 403):
http://httperrors-example.azurewebsites.net/Error/Other/403

But not this (returns default, 500):
http://httperrors-example.azurewebsites.net/Errors/Other/400

It seems the catchall route, "{controller}/{action}/{id}", handles the latter request, passing parameter "id=400" to ErrorsController action Other, which sets optional parameter code=null.

One fix: 1) change ErrorsController parameter name for action Other(...), from code, to id; and 2) change route "Error/{action}/{code}" to "Error/{action}/{id}".

After doing so, both URLs work as expected.

Note: noting only for future reference, as others may wish to directly call the Errors controller rather than handling via IIS.

Thank you,

Kevin

The solution works when run locally in debug but when I deploy to an IIS 8.5 server, the error pages all come up blank. W3 logs show 404s on /Home URLs. Although this could be an IIS configuration issue?