Stock transport order &1 cannot be used with transaction &2

Message type: E = Error

Message class: MEPO - New Purchase Order Dialog

Message number: 830

Message text: Stock transport order &1 cannot be used with transaction &2

What causes this issue?

In the delivery schedule for this purchase order, the quantities entered
by the user and the quantities confirmed by the
<DS:GLOS.3FFC8091B6F6D311A4910060B03C3B0E>availability check</>
("available-to-promise"/ATP check) are stored in different lines. The
transaction you have selected is not allowed for the processing of these
lines.

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?

Choose the Enjoy Purchase Order transaction <DS:TRAN.ME22N>ME22N</> to
change or <DS:TRAN.ME23N>ME23N</> to display this PO.
if you receive this message when navigating from a transaction, check
the <DS:TRAS.SU3>user parameter</> <LS>ENJ_CALL_ME23N</>.