Object could not be generated: Category &1, key &2

What causes this issue?

An error occurred during instancing of a business object when
processing your entry.
The error occurred when processing a data flow.
Either the business object is incorrect or the data flow is not defined
correctly.

System Response

The system cannot process your request further.

How to fix this error?

Check the Customizing settings of the data flow.
Check also in the Business Object Repository whether the object type
&V1& is correct, generated and released.

Error message extract from SAP system. Copyright SAP SE.