3172655 - Why did a Purchase Order or Invoice fail to send to the SAP Business Network with the error, "Invalid or unrecognized sender credentials?"

Why did a Purchase Order(PO) or invoice fail to send to the Business Network (BN) with the following error, "Invalid or unrecognized sender credentials"?

Response returned with status Code [401] of Type [Unauthorized] with message {Error:Invalid or unrecognized sender credentials. Please contact support with the Error Reference Number: ANERR-xxxxxxxxxxxxxxxxxxx for more details}.

KBA , migration source: knowledge@ariba , 12s2 ea , migrated on: 2022-04-02 14:15:51 , BNS-ARI-INV , Invoicing , BNS-ARI-PUR , Purchasing , BNS-ARI-PUR-SRV , Services Procurement , How To