Troubleshooting Messages in the Message Store 
The message store contains all the messages that are received by the Data Orchestration Engine (DOE) for processing. If during the processing of a message, an error occurs and the message is not processed by the DOE, you can reprocess the same from the message store. The message store provides various troubleshooting options using which you can troubleshoot the message and subsequently reprocess the message.
More information: Message Monitoring