Field name already exists

What causes this issue?

The field name entered already exists in the layout for this material
type.

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?

In order to prevent confusion or conflicts with the same field name in
other structure types, make sure that the field name entered is
consistent with the current material creation process.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.