Investment key & does not exist (Please correct)

What causes this issue?

The investment support key &V1& has been entered in the master record,
but is no longer defined.

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?

Define the investment support key &V1& again using the Customizing
functions in Asset Accounting.

Error message extract from SAP system. Copyright SAP SE.