Contracts belong to different product types

What causes this issue?

You can only copy loan contracts if the source and target loans are
assigned to the same product category.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check whether the product types of the loan contracts are assigned to
the same product category.

Error message extract from SAP system. Copyright SAP SE.