Unable to send email with Thunderbird or Outlook while connected on VPN

If you can’t send emails while connected to the VPN, it likely is because your email client application is using NON-ENCRYPTED ports for receiving and sending emails.Typically we block port TCP 25 on the ActiVPN networks to prevent spam and to prevent your password from being sent in CLEARTEXT / PLAIN.This can happen especially with old email applications or if you manually configured your email account. To resolve the issue:
  • You may need to switch to a newer email client such as Outlook or Thunderbird, or to manually configure your email client to use port TCP 587 instead of TCP 25. Here are some common configuration ports: be careful of only using the ENCRYPTED (with SSL / TLS ones) 


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