Settlement date & is not at a period end

What causes this issue?

Settlement date &V1& is not at the end of a period.

System Response

When you are using periodic partial payments, the system only allows
<DS:DE.PADAT>settlement dates</> that fall at the end of periods.

How to fix this error?

Check your entry or delete the settlement date, if necessary.

Error message extract from SAP system. Copyright SAP SE.