Outlook quarantining emails triggered by Auth0

Last Updated: Sep 10, 2025

Overview

Emails such as verification or password reset are being quarantined for Outlook based inboxes

Cause

Outlook has quarantining rules in place, which can consider the content of email templates "phishy"

Solution

If the email provider used by the Auth0 tenant has DKIM and SPF set up correctly, but emails are being quarantined by Outlook mailboxes and you have gone through the common issues here: https://auth0.com/docs/customize/email/troubleshoot-custom-email-provider-delivery-issues , there may be a hyperlink or image source within the body of the email that is triggering the Outlook rules.

For example, an image hosted on a different domain to the sender can cause emails to be quarantined, or a hyperlink.

If using a custom domain, this can be used for the automatically generated links for email verification or password resets, by enabling it in the tenant's settings:

https://auth0.com/docs/customize/custom-domains/configure-features-to-use-custom-domains#use-custom-domains-in-emails