Outlook error 0x80042109 Outlook is unable to connect to your outgoing (SMTP) e-mail server is shown when trying to send an email.


  • Check that ‘SMTP server requires authentication’ is checked in the settings for your account.
  • Check that your firewall is not blocking access through port 25
  • Try changing your SMTP port from 25 to your ISP’s alternative SMTP port. If you’ve subscribed to an DomainsFoundry SMTP plan check your plan details for available SMTP ports. If you can now connect then your ISP will have blocked access to port 25 to try and force you to use their services.