Users getting blocked while surfing site, adding products to cart, at checkout

I’m also got blogged from my own site [ redundant link removed ], when I tested as customer and tried to add product in cart. I’m getting this screen. It detecting real user as boats. The experience is different for different users and they are getting stuck intermittently at different places.

• This topic was modified 1 year, 8 months ago by Jan Dembowski.

The page I need help with: [log in to see the link]