'Package Building Result' value not compatible with doc. type &1 from &2

What causes this issue?

If you select a value in the <LS>Package Building Result</> field on the
<LS>Advanced Settings</> tab page of a freight unit building rule, this
restricts the document types that you can enter on the <LS>General Data
</>tab page. The following restrictions apply:
If you select <LS>Estimate Package Count Only</>, you can choose a
document type of the category <LS>Freight Unit</> (<LS>FU</>) only.
If you select <LS>Create Complete Package Hierarchy</>, you can choose a
document type of the categories <LS>FU</>, <LS>FO</>
(<LS>Freight Order</>), or <LS>TU</> (<LS>Transportation Unit</>).
If you use a TU type, the category must be
<LS>Package </>(that means <LS>Package Unit</>).
We recommend to use a TU type with category <LS>Package</> instead of an
FU type.

System Response

The document type that you have entered cannot be used, because it does
not match the criteria described above.

How to fix this error?

Select a different document type that fulfills the prerequisites.

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.