No scheduling agreement could be found

What causes this issue?

The system uses criteria sent by the customer in the IDoc to determine
the related scheduling agreement in the SAP System.
In your case, there is no existing scheduling agreement, or the criteria
specified by the customer does not match the scheduling agreement that
you have created for the customer.
The system checks the criteria as follows:

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

Customer/Material number
Customer number
Customer plant
Purchase order number or unloading point, if you have activated the
check in Customizing for scheduling agreements with delivery schedules
Usage indicator
General text
If this search is unsuccessful, the system also checks on the basis of
the customer/material number only.

System Response

The system ends processing of the IDoc.

How to fix this error?

We suggest you do one of the following:
Switch to the scheduling agreement change mode (transaction VA32) and
find the scheduling agreement manually. Enter the criteria yourself in
the "further search criteria" section of the change screen. If
necessary, correct the scheduling agreement.
Process the IDoc manually. In this way, you can review all of the data
in the different steps of the IDoc and correct it if necessary.
If the IDoc is correct, and you cannot find an existing scheduling
agreement, create a new scheduling agreement.

Error message extract from SAP system. Copyright SAP SE.