Outbound Email fails with the error org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 1; Content is not allowed in prolog
|Knowledge Article Number||000240388|
|Description||Sometimes outbound messages fail with the following error "org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 1; Content is not allowed in prolog.". You can see this exception under Delivery Failure Reason field of "Outbound Messaging Delivery Status " page.|
|Resolution||Salesforce will consider outbound messages delivered successfully only if the target endpoint returns the response in the below format.
Salesforce expects the above response with "Ack=true" to consider the successful delivery. If the response is not following the above format, you will be seeing the error "Content is not allowed in prolog"
Also if your response is "Ack=false", you would be seeing the error "SOAP response was a nack" as Delivery Failure Reason.