Hi,
The issue you are experiencing often occurs when the SMTP server you are using requires authentication. As the error message states, you must be authenticated before sending the
email. Please try the following steps to enable SMTP authentication and then check to see if the issue persists.
1. In the "Tools" menu of Outlook, click "E-mail Accounts".
2. Select "View or change existing e-mail accounts" and click "Next".
3. Select the POP/SMTP account for the Exchange server, and click "Change".
4. Click "More Settings".
5. Under the "Outgoing Server" tab, click "My outgoing server (SMTP) requires authentication".
6. Click "Use same settings as my incoming mail server".
7. Click "OK".
8. Click "Next".
9. Click "Finish".
Best regards,
Sott Atkins MCSE, MCSA
Partner Technical Lead - Outlook
Microsoft Technical Support
for Platforms and Business Applications
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