Error during Voquepay payment checkout

Having configured the ms Voguepay payment method with my merchant ID, I enabled it as a payment method for one of my products. But I am unable to Checkout successfully using this payment method

Having selected vogue pay as the payment method, I click proceed to payment and got the following error on this page:https://voguepay.com/pay/
This XML file does not appear to have any style information associated with it. The document tree is shown below.

MethodNotAllowed

The specified method is not allowed against this resource.

POST
OBJECT
0PDFZYK8B8SZG7K7

SMaeJybnQZ2HWI5CC/lZyrVX1KGWUT1LpsBEz6kMHZVc0G8PesacKe3YkU2BqC41T2IUNbkJGp4=

Please how do we resolve this.