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lmassip
Staff
lmassip
Staff
May 19, 2025

Troubleshooting TIP: FortiToken activation email fails due to Gmail SMTP authentication error

  • May 19, 2025
  • 0 replies
  • 1894 views
Description

This article describes a common issue where FortiGate fails to send the FortiToken activation email (QR code) to users due to SMTP authentication errors when using a Gmail account with two-step verification enabled.
Scope

FortiGate configured to send FortiToken activation codes via Gmail SMTP server.
Solution

When using a Gmail account with two-step verification (2FA) enabled, FortiGate cannot authenticate using the standard email password. This results in authentication errors such as:

 

session: rsp_state: auth2, code: 535 <----- Send mail failed

 

To resolve this issue:

  1. Log in to the Gmail account used for FortiGate email configuration.
  2. Go to Security -> App passwords.
  3. Generate an App Password.
  4. Use this App Password in FortiGate email settings under:

 

config system email-server 

    set password <App Password> 

end

 

  1. Test the connection again. After applying this change, FortiGate should be able to send activation emails with the QR code for FortiToken successfully.

 

For more information, refer to the Google support page: https://support.google.com/accounts/answer/185833?hl=en
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