Document type &1 has number range &2 with external number assignment

What causes this issue?

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

System Response

You have specified a reversal document type for document type &V1& which
has number range &V2& with external number assignment.
For Central Finance processing an internal number range is needed for
the configured reversal document type to avoid duplicate document
numbers.

How to fix this error?

Specify a different reversal document type with a number range with
internal number assignment.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.