Double Authentication in Signals NoteBook Standard

Hi,

I need a help on mail notification in Signals NB. If user is login to their Signals how he/she can get a notification regarding his/her login on the mail. Is there any option in Signals or if anyone can provide us the help on API for this?

If anyone other than a user is trying to log in (assuming he/she has a credential of user) than that User can track his/her email. It is a double authentication. If there is an OTP based mechanism in Signals than that also works.

Thank you.