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

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

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

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

New required configuration
For email sending to work correctly in Thunderbird, you must configure:
  1. SMTP port: 587 or 465
  2. Security: STARTTLS (587) or SSL/TLS (465)
  3. Authentication: enabled
  4. Password: normal (unencrypted)
How to change the outgoing port in Thunderbird
  1. Open Thunderbird
  2. Go to Account Settings



  3. Scroll down to Outgoing Server (SMTP)



  4. Select the server and click Edit



  5. Configure:
    1. Port: 587
    2. Connection security: STARTTLS
    3. Authentication: normal password



  6. 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 use the correct password (without old encryption settings)


For more information, you can contact us.