Data element & is still being used in aggregate &

What causes this issue?

A where-used list was executed for the data element which determined
that the data element is referenced in aggregates (views, lock objects
or match code objects).

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

How to fix this error?

If you want to delete the data element, eliminate the use of the data
element in the aggregate fields before deleting.

Error message extract from SAP system. Copyright SAP SE.