Magento – Paypal payments pro-Your payment has been declined. Please try again

If you do not want to have Paypal Express Checkout button displayed in the shopping cart you can turn it off in the Basic settings of Express Checkout. This will allow to have PayPal mark available on the Payments step only along with Pro. In this case customer will be forced to fill in all the fields before get to the payment page. Also in 1.9 you have an ability to skip order review page for Express and make checkout process even more shorter. See this link.

Pro can be activated with Express only, besides Express API is better than Standard since does not rely on IPN - able to process payment and create order at the same time.

Express Checkout has been canceled

is coming from

Magento\Paypal\Controller\Express\AbstractExpress\Cancel

Both express checkout and Standard methods, the cancel url's class is extended from this class:

You will find that class extends by

• Magento\Paypal\Controller\Payflowexpress\Cancel
• Magento\Paypal\Controller\Expres\Cancel