don't see the secure paypal browser

[steveralthouse]

I am trying to create a paypal button to accept payments in a Visual Studio asp.net application.

I get the button, but when I click on the button I get "Don't see the secure PayPal browser? We'll help you re-launch the window to complete your purchase.

After receiving the above message, the window then closes.

I am following the instructions from Integration Builder - Button Generator - PayPal Developer

Thanks in advance.