If a MigrationWiz mailbox batch reports completed yet users are missing mail, the first place I look is ApplicationImpersonation. A green status in the dashboard only means the job finished running. It does not prove anything migrated. The real indicator is the items count, and when that number is zero, it is usually a permissions problem disguised as success.

For mailbox migrations, the migration admin must have impersonation rights that apply across every mailbox in the source tenant, not only the admin account. EWS can authenticate the service account and still reject access to individual mailboxes if impersonation was granted at the wrong scope. In migrating over 200 Exchange mailboxes to M365 with MigrationWiz, I verified in the Exchange Admin Center on the source side that ApplicationImpersonation was assigned at the organization level before running any batches.

Do not close out a batch because the status pill is green. Check the item count first.

What credential scope validation are you running before your first MigrationWiz batch submits?

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