Fortnox error: 2001089

Error 2001089 – "Payment date cannot be earlier than invoice date" means that the integration platform is attempting to export a payment to Fortnox where the payment date is set to an earlier date than the invoice date. This is not allowed in Fortnox because logically, a payment cannot occur before an invoice has been issued.

How to resolve the issue

• Check the payment date in the integration platform and ensure that it is on the same day or later than the invoice date.
• If the payment actually occurred before the invoice date, the invoice date must be corrected to reflect the actual date. Adjust the invoice date backward to the same or an earlier date than the payment date.
• After adjusting the dates, re-export the payment from the integration platform to Fortnox.

Summary

Always ensure that the payment date is the same day or later than the invoice date. After making the necessary corrections in the integration platform, re-export and verify that the payment goes through without errors.