Problem
Sometimes when sending or replying to an E-mail you may receive a message stating:
"Delivery has failed to these recipients or distribution lists:
Lastname, Firstname
The recipient's e-mail address was not found in the recipient's e-mail system. Microsoft Exchange will not try to redeliver this message for you. Please check the e-mail address and try resending this message, or provide the following diagnostic text to your system administrator."
This error usually occurs if:
1. you reply to an E-mail you received before your Mail Migration
…OR…
2. you use the auto-complete in the To… field
Even though the E-mail addresses are correct, Outlook remembers the (old) 'server address' from before the Mail Migration. This means Outlook attempts to send the message to the old EUI server and not the new Microsoft server.
Solution
To resolve the issue:
1. When sending an E-mail remove all E-mail addresses that failed from the To… field
2. Click the To… button
3. In the Address Book drop-down box, select Global Address List
4. Search for the recipients that failed and add them to the To -> field
After you have sent an E-mail to someone using this method once, Outlook will remember the correct (new) 'server address', and you will not get the problem again.
However, if you send to a different E-mail address and get the error message again, simply repeat the steps above for that recipient.