If there is any pending invoice, the system will not let you make another order. You must first cancel or end pending payments in order to continue.
How to fix it?
In order to make a new shipment, you must first finish the pending shipments.
To do this, you must go to "Distribution> Orders processed" and finish or cancel the payment that is pending confirmation.
Once you have processed the previous order, you can proceed with the next one.
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