When I register for a new user from a regular web application, Auth0 sent 2 email verification: one appears from the regular web application name as the sender. The other exact same email appears to be sent from the auth0 tenant name. The verification code are different on each email.
Clicking the link sent from the tenant name is showing an error “Your email address could not be verified” although it does verify the email. Likely because the issue mentioned here Your email address could not be verified - #4 by anton.bagayev
Clicking the link sent from the regular web application name, does verify the email and correctly redirect the user to the specified “Redirect To” in the email template.
When I change user’s email, it also sends 2 verifications however there is a slight difference from registration:
Email verification from tenant name is sent to the old email address. Clicking the verification link, does not verify the new email and shows “Your email address could not be verified”
Email verification from the machine to machine application name (because the email change is implemented using API call from M2M application) is sent to the new email address. Clicking the verification link, does verify the new email.
Update: The issue was in my application code which uses devise gem. The way we implement re-send confirmation email from the app caused that method to be called by devise callback, un-intentionally sending the email again.