ON-PREMISE ENVIROMENTS:
For Microsoft Exchange Server 2010, 2013 or 2016
1. The ESM service running account MUST be granted Exchange "Receive-As" Permission on all mailboxes in the Exchange Management Shell
By using this cmdlet:
Open the command prompt as administrator, type the following line, and then press ENTER:
Get-MailboxDatabase | Add-ADPermission -extendedright receive-as -user <yourArchive ManagerUser or Group>.
2. The ESM service running account should also be a member of the Exchange View-Only Administrators Group so the ESM service can fetch all the messages from each mailbox back.
NOTE: If a new Exchange mailbox store is added after the Archive Manager is installed, the permissions for this group must be set again. Otherwise, an error may occur when the ESM processes mailboxes in the new mailbox store.