As part of your Email Archiving (ArcTitan) setup, a journaling rule must be created on your email server to allow email to automatically archive to ArcTitan.
If you are using the TitanHQ Platform, then you'll set up a journaling rule on the Platform. See Connect and Configure a Customer Account for more details.
If you are using ArcTitan as a stand-alone product, then to create a journaling rule, you need to know your journaling email address. The journaling email address has a common syntax using your company tag and your ArcTitan server name. For example, if you log onto https://archive-eu.titanhq.com/titan/company_tag, your journaling email address is company_tag@archive-eu.titanhq.com.