Samlink has some special rules concerning Finvoices.
B2C invoices with type code INV01 cannot have negative amount.
In addition the following details will be checked from ePI part of the message when you send Finvoice to bank:
- Beneficiary bank account ID is given and it is valid
- Amount is given
- Expiration date for payment is given and it is not in the past (EpiDateOptionDate)