You are on Exchange, sending mail from Outlook to someone you have sent mail to before, but this time the email is returned as undeliverable. The person you are sending to has recently been moved from Mirapoint to Exchange.
This is usually caused by bad (now outdated) data in the auto-complete entry for the recipient. This is a result of selecting the recipient from the dropdown list that appears when you begin typing in the “To:” field on the email message.
1. Run Outlook and log in
2. Open a new blank email
3. Begin typing the recipient’s name or address in the “To:” field, until you see them appear in the dropdown list.
4. Do not click on the recipient’s name, but using your arrow keys, select them in he list.
5. Press the “delete” key and check to be sure that the recipient’s name comes off the dropdown list.
6. Repeat steps 4. and 5. for every instance of that recipient.
NOTE: Sometimes the same person can be in the list more than once, so try first name, last name, different names, nicknames, etc. until you have removed them all.
7. Repeat steps 4. - 6. for each person that you have had problems sending to.
8. QUIT OUTLOOK.
NOTE: This step is very important - it won’t fix the problem if you don’t quit Outlook entirely.
9. Wait 30 seconds then run Outlook again.
10. Verify that the person no longer appears on the dropdown list when you begin typing their name in the “To:” field of a new email.