Specify target entries

What causes this issue?

You have selected one or more entries to copy.

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?

Edit the field contents. Please note that the key must be changed
because a second entry with the same name cannot be stored in the
system.

Error message extract from SAP system. Copyright SAP SE.