its commission junction, aka
www.cj.com in most cases kitty, those sponsors aren't accepting new applicants, that's usually the case but they may be accepting in the future that's why they still allow applicants. Best bet would be find a similar sponsor and use them and keep applying to the main ones.
They also may feel your site isn't appropriate or have the proper traffic base for what they want. Try going directly to the site and emailing their support or customer service for any advice you may need.