Sometimes the Data Load Service will come across a message that cannot be processed from the Journal Mailbox.
When a message in the journal mailbox cannot be processed, then message will be left in the inbox to be retried on the next cycle.
This is normal and is the expected behavior in Archive Manager 3.8
These messages will be reflected as error in the Application Event Log and in the wlog file.
To work on this problem, send an archive of these messages in a PST file and the latest data loader wlog file to email@example.com for analysis.