Check confirmed quantity for STOs not supported by advanced ATP check

What causes this issue?

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

System Response

You have selected the <LS>Advanced ATP</> checkbox. In at least one of
the ATP check control entries that use this checking group, you have
entered <LB>A</> in the <LS>Incl. Purchase Orders</> field. The advanced
ATP check does not support this feature.

How to fix this error?

If you want to use the advanced ATP check, check all check control
entries that use this checking group (in the
<DS:SIMG.SIMG_CFMENUOLSDOVZ9>Carry Out Control For Availability Check</>
Customizing activity) and enter a different option in the
<DS:DE.BESTP_APPL>Incl. Purchase Orders</> field.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.