My IPN is not loading on PayPal, it doesn't working

[Rono007]

Hi, I have been using paypal on my website for almost a year. Never had a problem. All of a sudden last week, when I click on "Instant payment notifications" in PayPal administration, it doesn't found that specific page and shows this.

https://www.paypal.com/webapps/mpp/page-not-found

So when new users pay via PayPal on our website, they don't get an access as they should and as they got before until it stopped working.

Website is www.andy-rono.com  

Sorry for my bad English, I'm Czech.