Can't recieve IPN with ASP.NET MVC

[rkitvn]

I've registered accounts at sandbox, set "buy button" at my site, created listener .aspx, like at the guide for asp.net integration.With sandbox private account I've used "buy button", and recieve the payment, but I can't recive the IPN. Set all the options of IPN, like link to listener and enabled it. In the IPN history always status of the notification is retrying. I've tried to set breakpoint, butit never stops here. Also I've sent fake httppost notification to my listener from the other computer and I've recieved it.What is wrong?Thank for Your help.