HTTPS Web Service Error: HTTP 0 Null, Peer Certificate Rejected by ChainVerifier

Dear Experts,

I'm configuring an interface with proxy to HTTPS web service (external WS) scenario.

When testing the interface I face the following error:

24.02.2015 19:51 151.722           Error Failed to call the endpoint: Error in cal over HTTP. HTTP 0 null

24.02.2015 19:51 :51 .722           Error SOAP: Call failed: java.io.lOException: Faied to get the input stream from socket:                                                   iaiksecurity.ssl.SSLCertificateException: Peer certificate rejected by ChainVerifier

24.02.2015 19:51:51.741             Error SOAP: Error occurred: corn.sap.engi1e.irrtertaces.rnessaging.api.exception.MessagingExcep1ion:                                                   iava.io.|OException: Failed to get the input stream from socket: iaik.security.sst.SSLCertificateException: Peer                                                   certificate rejected by Chainverifier

24.02.2015 19:51 :51 .742           MP: exception caught with cause com.sap.engine.interfaces.messaging.api.excep1ion.Messagi1gException:                                                                      iava.io.IOException: Faied to getttginput stream from socket@s§cgiy5§1.SSLCqtificateException: Peer certificate                                                        rejected by Chainveritier

24.02.2015 19:51:51.745           Error Exception caught by adapter framework: java.io.lOException: Faied to get the input stream from socket:

                                                  iaik.security.ssl.SSLCertificateException: Peer certificate rejected by Chainverifier

24.02.2015 19151151746           Error Delivery of the message to the application using connection SOAP_ht|p;!Isap.comIxiIXlISystem failed, due to:

                                                  com.sap.engine.interfaces.messaging.apiexception.MessagingException: java.io.lOException: Failed to get the input                                                   stream from socket fail<.security.ssl.SSLCertiticatzeException: Peer certificate rejected by Chainverifier. Setting                                                   message to status failed

24.02.2015 19:51:51.746           Error Message status set to FAIL

The first error message seen is HTTP 0 Null, but all the next message error refer to Peer certificate rejected by Chainverifier.

I believe we've test to access the web service url via https from the PI server using a web browser and succeeded.

What I'm confused about is that: Does this error is because PI cannot connect to the web service (HTTP 0 Null) then it causes the Certificate error? Or is this because the Certificate error that cause the HTTP 0 Null error?

Thank you,

Suwandi C.