This is not an error, this is a warning that does not affect the received package status. On the NP website, if you enter the ttn number, you will receive the current status of the parcel, to obtain detailed information about the parcel, you are asked to enter the number of the sender or recipient. So it is with api, for complete information, she asks to give her a number as well. Therefore, this message has no effect on the operation of the system.
Process
https://crm.ohrana.ua/admin/customorder/dostavka-i-peremeshchenie/2351890/edit/ - the request that is indicated on your screen was sent by the New Mail block in the process to receive the current status of the parcel directly from the NP. If you do not open the process - the request will not be sent, if you do not delete this block from this stage - the request will not be sent either