Hi Diego,
Yes XI system was restarted after the certificate import.
Here is more details about the error:
Delivery
of the message to the application using connection
SOAP_http://sap.com/xi/XI/System failed, due to:
com.sap.engine.interfaces.messaging.api.exception.MessagingException:
iaik.security.ssl.SSLCertificateException: Peer certificate rejected by ChainVerifier
Thanks
Pankaj