Closure of port 25 | How to modify the port in Outlook

Closure of port 25 | How to modify the port in Outlook

Due to a security update, port 25 has been disabled for sending emails.

Additionally, the authentication system has been unified, so it is now necessary to use a regular password together with a secure connection.

New required configuration
For email sending to work correctly in Outlook, you must configure:
  1. SMTP Port: 587 or 465
  2. Security: STARTTLS (587) or SSL/TLS (465)
  3. Authentication: enabled
  4. Password: regular password (without manual encryption)
How to change the outgoing port in Outlook
  1. Open Outlook
  2. Click on File


    Go to Account Settings > Account Settings


  4. Select your email account and click Change


  5. Click on More Settings


  6. Go to the Outgoing Server tab
    1. Enable: "My outgoing server (SMTP) requires authentication"


  7. Go to the Advanced tab
    1. Change the outgoing server (SMTP) port to:
      1. 587 (with STARTTLS)
      2. or 465 (with SSL/TLS)
    2. Under encrypted connection type, select the corresponding option


  8. Click OK and then Next
  9. Save the changes
Common issues
  1. If you cannot send emails, check that port 25 is not configured and that Outlook has correctly saved the changes.
  2. Verify that SMTP authentication is enabled
  3. Make sure you are using the correct password (without old encryption configurations)


For more information, you can contact us.