Confirmation control key & for confirmation category & not maintained

What causes this issue?

Confirmation control key &V1& with confirmation category &V2& is not
allowed. The confirmation relating to PO number &V3&, item &V4&, cannot
therefore be adopted in the document.

How to fix this error?

Change the confirmation control key in the purchase order item.
If necessary, contact your system administrator. The latter can maintain
confirmation control key &V1& with confirmation category &V2&
using the Customizing facility.
<DS:SIMG.SIMG_CFMENUOLMEOMGZ>Set up confirmation control</>

Error message extract from SAP system. Copyright SAP SE.