Subcontracting purch. req. for subcontracting planned order &1 not found

What causes this issue?

You want to convert <LS>Supply Network Planning</> (SNP) orders into
<LS>Production Planning and Detailed Scheduling</> (PP/DS) orders. You
have selected a subcontracting planned order in the location of the
<DS:GLOS.36407BAE5D6F3184E10000009B38F984>subcontractor</> (supplier
location) for conversion. You have <ZH>not</> selected the order (that
belongs to the planned order) for the subcontracting stock transfer
from the supplier location to your location (destination location).
However, in subcontracting, you have to convert the subcontracting
planned order and subcontracting stock transfer order; it is not
possible to convert the subcontracting planned order on its own.

System Response

The system does not convert the subcontracting planned order.

How to fix this error?

To select the subcontracting planned orders for conversion, you have
the following options:
Select the subcontracting planned order and the subcontracting stock
transfer order for conversion
Only select the order for the subcontracting stock transfer
In this case, the system automatically selects the subcontracting
planned order too.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.