Hotmail blocking auth0 mails


It seems auth0 mails are blocked on two different hotmail accounts. We tried using smtp.office365 and sendgrid, in both cases, the mails never arrive.

Any idea what might be happening?


Technically, if you refer to the email sent from one of your own tenants this would imply you having setup your own email provider. Given you mention Office 365 SMTP and SendGrid I believe this is your scenario.

In this scenario, a big chunk of the things that can cause emails to not be delivered would rely solely on the email provider you have configured and in most cases unless it’s related to the actual content of the emails it would be really weird for the issue to be Auth0-specific.

Are the two Hotmail accounts under your control or are these associated with your own end-users?

Those are our own private email accounts. One was used for the very first time with that specific domain, so no rules were setup.
The other was used in the past for testing without any issues.

I insist on the fact that our gmails and work emails all work. Only our adresses do not receive the confirmation emails.

Also, emails send using the same sendgrid apikey/setup to the same hotmail adresses do arrive. Only auth0 send emails do not arrive on those hotmail adresses.


We found the issues (sendgrid ip blacklisted).
Thanks for the help. (no idea why office was impacted).


No worries, glad you found the issue and the situation is addressed.