Inbound invoices from OBN to Cloud failing with Error 4203 - OXTA Malformatted Response

Summary:

We are using OBN to send POs to suppliers and receive invoices from them. The outbound POs are working fine. The inbound invoices are successfully received by OBN. However, the OBN to Receiver process is failing with the Error 4203 - OXTA Malformatted Response error. The self test between the Cloud environment and OBN is successful. Any ideas on what the issue could be? The supplier site setup for B2B is also setup.

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Cloud pod and OBN are on 25C

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