Billing plan data cannot be processed for document type &1

What causes this issue?

The referencing procedure &V2& contains fields for the header billing
plan.

System Response

According to the settings in Customizing, you cannot create a billing
plan for document type &V1&.
The reference to the master contract &V3& is therefore deleted.

How to fix this error?

You can only create the reference if you change the Customizing
settings so that billing plans can be used or if you remove the fields
for table FPLA in the reference procedure.

Error message extract from SAP system. Copyright SAP SE.