A database index necessary for using the payment reference is missing

What causes this issue?

If open customer items are to be determined using the payment
reference, a corresponding database index must exist. This is not the
case for this installation.

System Response

You cannot activate the desired option.

How to fix this error?

Ask your database administrator to create an index for table
<ZH>BSID</> which uses the field <ZH>KIDNO</> as the next field after
the client. The index must be described and created using SAP
transactions so that information on the existence of the index can be
stored in the SAP system.

Error message extract from SAP system. Copyright SAP SE.