Verification Email and Welcome Workflow with Azure Communication Services Email Provider Configuration

Observations on Email Verification and Welcome Email Delivery

I’ve been conducting tests using different emails to sign up for accounts via email-password and Google social connection. Here are my findings and need help finding answers for certain scenarios from the Auth0’s side:

1. Personal Gmail (@gmail.com) Accounts for Email-Password Signup (not social connection)

  • Instant verification email.
  • Followed by an instant welcome email after clicking verification URL.
  • Instant password reset email also received.
  • Working as expected.

2. Google Social Connection Register

  • Auto-verified as Google social connection.
  • Instant welcome email.
  • Password reset not applicable since using Google account.
  • Working as expected.

3. {university_name}.edu, etc. Email (Gmail Exchange- University email) for Email-Password Signup (not social connection)

Initial Observation:

  • Azure logs indicate email was sent for (Verification email) and the state of the user in Users section of Auth0 was pending and still not verified.

  • No emails received initially.

  • After 4 minutes past account creation, the user’s email status changed to verified automatically (similar to Google social connections) and the welcome email was sent automatically (since the verification was already reflected- despite this being a regular email-password register).

  • There was a 4-minute delay between account creation and the welcome email. There was an automatic change in verification status for email-password type account (Why is this happening?)

    Account Deletion and Retry of whole process:

  • Deleted the said university email linked user account and repeated the signup process.

  • Waited for some time and this time, the email did not auto-verify and remained pending verification.

  • Logs indicate that the email was delivered, but no email was received in the inbox.

  • No welcome email received since the verification email was not received.

  • Logs did not show any failure messages.

    (After 15-20 minutes)

  • The .edu email eventually converted to verified status without receiving a verification email, and the welcome email was received after a significant delay.

  • This might be related to the behavior of exchange emails in the verification process? I would like to know why it is behaving this way and how can it be fixed? Why are such emails despite being registered with email-password having such behavior and why the delay in the status change?

4. Yahoo Email for Email-Password Signup (not social connection)

  • SMTP Status Code: 554
  • Failure message: “Message permanently deferred due to unresolvable RFC.5321 from domain.”
  • This is Azure specific issue and not of Auth0 so this observation can be ignored.
  • Just listed this for documentation to see if someone in the community faced a similar problem, they could share their solution.