Table field & not found

What causes this issue?

According to the valuation rule, field &V1& is to be used for
automatic valuation. However, the system could not find the field.
Only fields in table AUFK can be used for automatic valuation.

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?

Maintain the valuation rules in table TKLCO.
<DS:TRAN.SM31>Table maintenance</>

Error message extract from SAP system. Copyright SAP SE.