Field selection for account assignment category & not defined

What causes this issue?

The field selection string that controls the account assignment fields
which are to receive input for the relevant
<GL:account_assignment_category>account assignment category</> has not
been defined.

How to fix this error?

INCLUDE SYSADMIN1_NA
The latter can define the field selection string using the Customizing
facility.
<DS:SIMG.SIMG_CFMENUOLMEOME9>Maintain account assignment categories</>

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