You can no longer select new master data

Message type: E = Error

Message class: CO - PPC order processing messages

Message number: 506

Message text: You can no longer select new master data



What causes this issue?

You cannot select a new routing / bill of material, due to one of the
following reasons:
Components have already been issued for the order.
Confirmations have already been entered for the order.

Error message extract from SAP system. Copyright SAP SE.