PayPal Express Checkout button failure

I cannot get the button “Check out with Paypal” to work correctly with PayPal Express. Hopefully someone here can see my error.



Scenario and config for PayPal Express Checkout



Processor: PayPal Express Checkout

Username:

Password:

PayPal authentication method: Certificate or Signature

Certifiate name: If used

Signature: If used.

Currency: Australian Dollar

Test/Live mode: Test and Live



If I select the button “Check out with Paypal” in the Cart contents page, the button directs to URL [url]http://mydomain/payments/paypal_express.php[/url] and goes no further and a blank page is displayed.



If I were to bypass the Cart contents page and proceed directly to the Checkout, and “Place order”, then cscart redirects to Paypal and payments can be successfully made.



This is happening on 2 websites hosted on Jumba. A fresh 2.1.2 install and an upgrade from 2.1.1 to 2.1.2.



Reverting back to 2.1.1 did not rectify this issue. (I did not have PayPal setup on 2.1.1 I merely tried a revert for problem solving)



Folder and file permissions are 755 and 644 respectively.



Regards

Raeandy