During the purchase process of Borlabs Cookie you can specify your VAT number.
If you receive the error message You need to enter a valid VAT number, first check if you have entered your VAT number completely. If the number is correct, the EU servers of the VAT Information Exchange System (VIES) may be down.
You can test the status of the servers and your VAT number via the EU Commission VAT number validation website.
https://ec.europa.eu/taxation_customs/vies/vatRequest.html
Enter the requested information there and click Check. If the servers are down, you can simply specify your VAT number after purchasing Borlabs Cookie.