We recently switched one of our clients from an on-premise exchange server to office 365 and one user had access to all other users mailboxes by opening them automatically through outlook.
E-Mail Accounts > Server Settings > More Settings > Advanced > Open these additional mailboxes
When I try to add the same users in Open these additional mailboxes I receive the error "Cannot expand the folder"
We had migrated these users via cutover migration.
Would I need to re-assign permissions for that user? If so what permissions would I need to assign?
Thanks for any help