Redirect not redirecting at all

I am recreating a website in Drupal that was built using ASP.NET.

The new website has much of the same or similar content so I'm using Redirect to help users who have pages bookmarked, etc.

For example, the old ASP.NET site had a Board of Directors page: www.domain.org/BoardOfDirectors.asp

The new Drupal site has a similar page: www.domain.org/board-of-directors

So I created an URL redirect:

From
http://domain.org/BoardOfDirectors.aps

To
board-of-directors

But when I put the following in my browser address: http://www.domain.org/BoardOfDirectors.asp

I just get an ugly "Not Found" page:

The requested URL "/BoardOfDirectors.asp" was not found on this server.

It doesn't even show my custom 404 page, but just black text on a white page.

Any idea what is going on?