This setting is for Global SMTP subscribed users.

1. Start Outlook. Go to File tab, and click Account Settings.

2. Select your email account and click Amend.

3. Click More Setting in Internet Mail Setting.

4. Click Advance tab and update the SMTP port from 25 to 465, 587 or 2620

5. Click Apply to complete setting.

6. Please ensure that  "My outgoing server (SMTP) require authentication" is enabled.