The workaround seems to work, but it is just that, a workaround. Very annoying to have to train a handful of users to do this. We tried opening a ticket with Quickbooks Support, but after all of the backups, company file verifications and rebuilds, logging in test accounts from gmail, yahoo, etc into Outlook, etc, nothing seems to have fixed the problem. After nearly 2 hours, Quickbooks Support was unable to find a solution, leading me to believe that it is an issue with the last software update. Even a new company file is experiencing these issues. I believe an escalated investigation of this issue is warranted.