It means that the EU VAT site is currently experiencing problems. Just leave the field blank and send us your VAT number and scanned copy of the documents. We will update your account.
If you are trying to input a VAT number from outside the EU, we cannot accept that. Please leave that field empty.
You can also try to manually validate your VAT number on this authoritative website.
- log into your account on the website.
- go to "Profile" or "Payments" tab, there you will see the current account credit balance.
You can also consult the detailed cost of each conference call you made under "my Conference", "history".