HTTP error in RWB

Hi All,

We have lakhs of messages in "to be delivered" status.... i manually canceled them from RWB... now i want to delete them are they are lakhs in number...ny standard job/report to delete them.....

Also for new triggered record..it is going in NDLV status.... with error...

Transmitting the message to endpoint http://server.dpsg.net:port/sap/xi/engine?type=entry using connection MDM_http://sap.com/xi/MDMAdapter failed, due to: com.sap.engine.interfaces.messaging.api.exception.MessagingException: Received HTTP response code 500 : Internal Server Error

what this error means?

Regards,

Rashmi