OAuth redirect_url – not working

Hi, I am trying to use your instagram feed plug-in & I have entered all the correct login info & when the pop-up opens asking me to “authorize” my account.. I click it & it says

Error 404 – Not Found

The document you are looking for may have been removed or re-named. Please contact the web site owner for further assistance.

I am not sure what to do? Thanks.

http://wordpress.org/plugins/instagram-for-wordpress/