Forms not connecting to PayPal.

I have checked the forms on your account and they seem to be redirecting to the PayPal payment page without any problem: 

I have noticed that your payment field is not required and your products have a quantity selector, please note that even if your users select a product, but if they leave the quantity field empty the form will not redirect to the PayPal payment page. 

I would recommend you to set the field to be required instead: 

If the issue persists, please provide us more details about it, we will be glad to take another look to your forms.