BR-DE-16: The invoice uses one of the VAT category codes S, Z, E, AE, K, G, L or M, but…
What it means
The invoice uses one of the VAT category codes S, Z, E, AE, K, G, L or M, but does not state the seller's VAT identifier or an equivalent tax registration identifier.
How to fix it
Add the seller's VAT identifier or tax registration identifier whenever one of those VAT categories is used.