One of our users is experiencing problems rescheduling meetings and notifying attendees outside of our company of the reschedule. The message that gets sent automatically informing the attendee of the new time never makes it to the recipient, though the initial meeting request and regular email goes just fine. The user first gets a delivery delayed message, followed by a delivery failed message. I and others are able to send out these meeting reschedule changes without a problem. I understand there is still a lot of troubleshooting left to do, but dont really know where to look from here.