PO matched Invoices are not imported

Summary:

We are receiving invoices via OBN and then importing them to cloud using import ESS. For one specific vendor the PO matched invoices are not getting created in cloud. When the import process is run the invoices are not created and the log shows no data. How can we ascertain what the issue is?

If invoices are PO matched , what are the related PO details that system needs to create invoices. Also note while we are receiving invoices via OBN , we see PO order date as well in the OBN message. Does this date need to match with the order date that exist in cloud for the PO