No transfer, since not all items can be transferred together

What causes this issue?

It is defined in <DS:SIMG._FICABTTP_FQZ16>Customizing</> that all
selected open business partner items must be transferred collectively.

System Response

The transfer was not executed.

How to fix this error?

Check the reasons why individual business partner items were not
permitted for transfer and remove the cause if necessary.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.