This article will step you through how to update the SMTP port used by the Mail app in Windows 10.
Don't use Windows 10? Check the help topics for your device or Operating System.

1. Start by opening the Mail app from the Start menu
2. Click the Settings icon in the lower-left
   
   
   
   
3. Click Manage Accounts
4. Click on your E-mail Address from the list shown
   
   
   
5. Click Change mailbox sync settings
   
   
   
6. Scroll downwards and select Advanced mailbox settings
   
   
   
7. Update Require SSL for outgoing mail to checked
   
   
   
8. Click the Done button to confirm the changes
9. Click Save to save the changes

Still stuck? Log a support call using the 'Create new ticket' option above!