Did you change your userid or password on eBay? If so, you have to change it on AS to match. Click on "Modify Account" at the top of the main snipes page and you can make the change. If you didn't change your eBay info then perhaps you just typed your userid or password incorrectly. Try entering them again. If these fail, then go to
http://support.auctionsniper.com/ and ask there what you should do.