title: Vendor systems returned INVALID or ERROR in response to notification POST - Sagepay Server
body: <p>Ive built 2 websites using opencart 2 (many more on Opencart 1) and both are setup to take Sagepay Server payments, But its now come to light that both sites Sagepay payments are failing when Sagepay tries to talk back to opencart to give the green light. This means no failure email notification is sent to the store owner, and the sale is cancelled at Sagepay? as you can imagine both store owners are not happy. I contacted Sagepay to see what was happening and they told me the payments were failing with the below Error, but as far as Sagepay was concerned the payments had passed all tests, but because the calling website could not send the correct response back to Sagepay, they had to cancel the transactions!</p>
  
  <p>Looking at how Sagepay works, it seams sagepay returns autorisation to Opencart and then opencart has to say whether its going to accept the payment based upon what is being sent, and it seams this is where opencart 2 is failing to respond correctly?</p>
  
  <p>Is this yet another OC2 bug? </p>
  
  <p>Has anyone come across this and how do I put this right </p>
  
  <p>One site is on OC 2.0.2.0 and the other one is 2.0.3.1
  Everything is setup correctly in payment module and IP Address logged with sagepay etc.., its just a problem after payment authorisation.</p>
  
  <blockquote>
    <p>Transaction completed but Vendor systems returned INVALID or ERROR in
    response to notification POST. Transaction CANCELLED by the Vendor.</p>
  </blockquote>
  
  <p>This is a really big problem, and not sure how to go about fixing this, as Opencart 2 is meant to be able to take sagepay payments out of the box, once a few settings are added in the admin section, but it seams its not setup correctly to do so.. I cant believe no one else has come across this?</p>