WordPress Network: Cannot access WP Admin after address change

I have a website set-up at tawilkinson.com and several subdomains. I have a wordpress Network set-up to control all of my sites.

I had everything set-up fine but I wanted one of my blogs to be reachable at tinkertailorsoldiersponge.com. I went to the site settings page of the network and set the site home and url to tinkertailorsoldiersponge.com. The blog works fine and can be viewed as expected.

When I try to login to the wp-admin panel though I cannot login. If I put in an incorrect password or username it returns an error as expected. When I input a correct user and password it just returns me to the login page with no error reported.

I have tried looking through the database and cannot find any incorrect references to the url. What have I missed?