During schema generation, non-supported types were found

What causes this issue?

During generation of the XML schema from the existing context,
attributes were found that are typed with non-supported types. These
non-supported types include structures, table types, and reference
types. The corresonding attributes were ignored and not included in
processing.

System Response

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

How to fix this error?

If you wish to have structures or table types generated into your XML
schema, create in the context a node with the corresponding cardinality
(...1 for structures, ...n for tables), and define the fields of the
corresponding type as attributes under the respective node.
Reference types cannot be supported, for technical reasons.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.