VAT number not validating

Morning guys, I manage a website which is set up so that when customers enter their eu vat numbers the website is supposed to deducting the vat.

This is not currently working. Nothing has been changed or added to the site except updates and it only happened over the weekend.

VIES is working, just tested it.

Any ideas on how to troubleshoot this please?

The page I need help with: [log in to see the link]