Error seen in the DSA.log
"Error 0xe300000c. Cannot apply Mailbox Security Descriptor to Exchange Store (Server=xxxx.xxxx.net, MailboxGUID=xxxxxxxxxxxxxx, HomeMDB=
In particular note the "RPC error 0x80070005. Access is denied"
The permissions for the QMM AD Domain Pair service account on for the Target Domain are not sufficient.
The permissions assigned to the Domain Pair/Active Directory service account on the target does not meet the minimum permissions required. Review the permissions requirements in the Migration Manager System Requirements and Access Rights pdf document (MigrationManager_8.X_SysReqAndAccessRights.pdf) or refer to the following article:
"Minimal Permissions Required by Migration Manager Service Accounts"
Specifically note the section "Directory Synchronization accounts and minimal rights:"
#3. Full Control on the Microsoft Exchange System Objects container