Select a link object as reference object

What causes this issue?

You are trying to create an order or a notification for a link object,
but have not yet selected an object.

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?

Place the cursor on a link object. This object will be entered in the
notification or order as the object referred to.

Error message extract from SAP system. Copyright SAP SE.