You cannot select 'X' for this inspection type

What causes this issue?

You can only enter the value "X" (an inspection lot for each purchase
order item, order item and batch) for inspection types of inspection
origin 01 and 04.

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?

Enter a valid value (BLANK, 1 or 2).

Error message extract from SAP system. Copyright SAP SE.