Invalid vAT number

Try searching for the company in the CBE (Central Business Register), where you can also search by name.

You can often find the company number on Google or on the website. Otherwise, give the restaurant a call ;)

Are there 10 digits in the number? It should be 10 digits, with the first digit being either a 1 or a 0.

But as LD rightly says, try searching the KBO: https://kbopub.economie.fgov.be/kbopub/zoeknummerform.html

Thank you everyone, I was stuck on that too!