Error
Required: Payment term
Required: Payment condition
Translation: Verplicht: Betalingsconditie / Betalingsvoorwaarde
Cause
You have not yet defined Payment Conditions in Financial in the setup of the linked Exact Online account, however, this is mandatory.
Solution
Go to your Exact Online administration settings in the top left and go to the Financial tab. At General > Payment term (Sales), select a default payment condition: