Ariba interface is failing in SAP PI with the Error: Can’t parse the document, HTTP 200 OK.

1. Follow SAP Note Support of WhiteSpaces in the SOAP Response on PI side.
2. Increase job frequency on ERP so that it decreases the number of records fetched from Ariba and it can be completed within timeout limit set in PI.
3. For P2P scenarios, P2P could be sending SOAP Fault messages without SOAP Envelope and PI standard SOAP Adapter does not recognize the message format, see How can we get the error message enclosed within envelope in web services?

End point Configuration issue at the external system, connection timeout or P2P SOAP Faults lacking SOAP Envelope.

Full error message shown in the PI:

Information SOAP: Request message entering the adapter processing with user Guest
Information SOAP: Target url: https://s1-2.ariba.com/Buyer/filedownload?realm=XXXX
Error Failed to call the endpoint: Error in call over HTTP: HTTP 200 OK
Error SOAP: Call failed: java.io.IOException: Cant parse the document; HTTP 200 OK
Error SOAP: Error occurred: com.sap.engine.interfaces.messaging.api.exception.MessagingException: java.io.
IOException: Cant parse the document; HTTP 200 OK
Error MP: exception caught with cause com.sap.engine.interfaces.messaging.api.exception.MessagingException
: java.io.IOException: Cant parse the document; HTTP 200 OK
Error Exception caught by adapter framework: java.io.IOException: Cant parse the document; HTTP 200 OK

Core Procurement > Core Administration > Application Integration (between Buying & Sourcing)
Core Procurement > Core Administration > Webservice Integration
Strategic Sourcing > Strategic Sourcing - Application Integration (BUY & SRC)
Strategic Sourcing > Strategic Sourcing - Web Services
Supplier Information & Performance Management > Supplier Information & Performance - Management Integration