Node &1: Collection type &2 is not allowed

What causes this issue?

Possible values for the collection type are collection, quantity, list,
and tree. These values have the internal codes 01, 02, 03, and 04.
Currently, only the collection type List (03) is allowed.
The node &V1&, however, has a collection type with the internal code
&V2&.

System Response

Error message of the syntax analysis.

How to fix this error?

Assign the node an allowed collection type.

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.