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 normal password along 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: normal (not encrypted)
How to change the outgoing port in Outlook
  1. Open Outlook and go to File


  2. Go to Account Settings > Account Settings


  3. Select your email account and click Change


  4. Click on More Settings


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


  6. Go to the Advanced tab
    1. Change the SMTP port to 465
    2. In encrypted connection type, select SSL


  7. Save the changes
Common issues
  1. If you cannot send emails, check that port 25 is not configured and that Thunderbird saves the changes correctly.
  2. Verify that SMTP authentication is enabled
  3. Make sure you are using the correct password (without old encryption settings)


For more information, you can contact us.

    • Related Articles

    • Closure of port 25 and changes in email authentication

      Important: If your email client is still using port 25 for sending emails or has outdated authentication settings, email sending may stop working. What should you do? You should review your email client settings and update: the outgoing port (SMTP), ...

    • Closure of port 25 | How to modify the port in Android

      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 normal password along with a secure connection. New required configuration For email ...

    • Closure of port 25 | How to modify the port in Mail de Mac

      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 normal password along with a secure connection. New required configuration For email ...

    • Closure of port 25 | How to modify the port in iPhone

      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 normal password along with a secure connection. New required configuration For email ...

    • How to add cdmon mail in Outlook (new version 2024)

      Professional email account IMPORTANT: For security reasons, port 25 has been disabled for sending emails. If your email client is configured with this port, you will need to update it in order to continue sending emails. New recommended ...