This option supports at a minimum Microsoft Exchange 2010 for on-premises mailboxes and Office 365 Exchange Online.
- All approvers and the service account must have a valid Exchange on-premises or Office 365 Exchange Online inbox.
- Distribution lists should be used for approval groups.
- Ensure that the proper Exchange certificates are installed on the GPOADmin server if certificates are being used in your Exchange environment.
- You must restart the GPOADmin service when you enable or disable this option.