Event ID - 4084

Event Id4084
SourceMSExchangeIMC
DescriptionThe Internet Mail Service did not start because the custom routing program could not be loaded. Verify that the setting for the custom routing program in the Routing tab of this services object in the administrator program points to a valid DLL. If no custom routing DLL file exists, then remove the setting.
Event InformationAccording to Microsoft:
Inbound Journaling: To journal inbound Simple Mail Transfer Protocol (SMTP) e-mail, create a registry string value named InboundJournal in the Extension key. Set the InboundJournal value to the e-mail address of the mailbox that will act as the journal mailbox. If you use a distribution list (DL) as the journal mailbox, you can journal mail to multiple mailboxes and it is very easy to change the journal mailbox. Microsoft recommends that you also remove the SMTP address, so that the mailbox cannot be attacked from the outside, and hide the mailbox from the address book, so that the mailbox is difficult to attack from the inside. You can then set the address to the X.500 address of the DL.
If you enable inbound journaling, you must also create a registry string value named InboundJournalNDR in the Extension key. Set the InboundJournalNDR value to the e-mail address to which you want non-delivery reports (NDRs) that are generated by journaled inbound e-mail delivered. As with the InboundJournal value, remove the InboundJournalNDR values SMTP address and hide the mailbox from the address book. Microsoft recommends that this recipient reside on the same server as the Internet Mail Service Extension.
Outbound Journaling: To journal outbound SMTP e-mail, create a registry string value named OutboundJournal in the Extension key. Set the OutboundJournal value to the e-mail address to which you want the journal e-mail delivered. If you use a DL as the journal mailbox, you can journal mail to multiple mailboxes and it is very easy to change the journal mailbox. Microsoft recommends that you also remove the SMTP address, so that this mailbox cannot be attacked from the outside, and hide the mailbox from the address book so that the mailbox is difficult to attack from the inside. You can then set the address to the X.500 address of the DL. If you enable outbound journaling, you must also create a registry string value named OutboundJournalNDR in
Reference LinksXFOR: Installing Internet Mail Service Extension Imsext.dll

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