We currently run Exchange 2010 and are migrating users onto Outlook 2010 from 2007.
Our Client Services group has Full-Access and Send As permissions(as well as send on behalf) to clientservices@ourdomain.com; on 2007 there was never any problem. With Office 2010 they can send for about a day; that is immediately after the upgrade, or creating a new Outlook profile. They then start receiving Undeliverables stating they don't have permission to send on behalf of this user.
This has been an issue for about a month now, trying many different scenarios to fix the problem and the only one that seems to work is to uncheck Cached Exchange Mode. The issue is not present if using OWA either, this makes me think it's client side.
Thanks for any help,
-Wil