Set type cannot be edited with transaction COMM_ATTRSET

What causes this issue?

The set type was not created using the <LS>Maintain Set Types and
Attributes</> transaction in the product master (COMM_ATTRSET), or it is
a standard SAP set type that was created manually (not generated).

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?

Make your changes using the transaction originally used to create the
set type. Standard SAP set types that were created manually cannot be
displayed using a set type transaction as the COMC_SETTYP_ATTR entries
required to do this do not exist.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.