Passwordless Verification Email - Failed Sending Notification "Error sending email: self-signed certificate"

Hi there we are currently experiencing a critical issue with our Auth0 setup. I’ve filed an internal support ticket (02343610) about this but not heard anything back for well over 2hrs.

Earlier today at around 10AM CET we noticed we were suddenly having failing verification emails in the logs with the error that is in the subject line of this topic. Initially we believed we must have changed something on our end with our DNS records, SMTP setup etc. as we use an external provider but this was NOT the case at all. We’ve then switched back to the Auth0 email provider instead but this does not successfully send either now (despite it producing logs for our instance that report a successful email send). I’ve checked a new, separate instance and this works fine but seems to be an issue currently effecting our production and development Auth0 instances for our app.

Any direction or pointers here would be greatly appreciated as we have had multiple user reports now and would like to resolve this issue as quickly as possible for our users.


1 Like

Sharing the workaround from support to switch from port 587 (StartTLS) to 465 (SSL) which resolved the issue and we are now able to use our external provider :partying_face:


Thanks for sharing! We were facing the same issue, do you have any idea why port 587 is not allowed all in a sudden?

Could you specify where we can switch that port?

You can find this setting under Branding (on the left panel on the dashboard) → Email Provider → if you have selected a custom SMTP provider then there will be a port number shown which you can change.

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