Production line & does not exist

What causes this issue?

You have entered a production line that does not exist in the system as
a work center.

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?

INCLUDE NA_EINGABE_PRUEFEN
Choose a production line that has already been created as a work
center, or create a work center with this number.

Error message extract from SAP system. Copyright SAP SE.