fatalPeppol BIS Billing 3.0profileUBL
For the Greek Suppliers, the VAT must start with 'EL' and must be a valid TIN number
The Greek supplier's VAT identifier is not EL followed by a valid TIN.
Greece uses EL, not GR, in the VAT identifier: EL123456789. The country code in the ADDRESS stays GR - the two differ and that is the usual mistake.
UBL — context cac:AccountingSupplierParty[$isGreekSender]/cac:Party/cac:PartyTaxScheme[normalize-space(cac:TaxScheme/cbc:ID) = 'VAT']/cbc:CompanyID
substring(.,1,2) = 'EL' and u:TinVerification(substring(.,3))