Much like this message, we are using auth0 with passwordless authentication.
We recently faced users getting their emails several minutes after they requested a code: too late for the OTP to be still valid. Our OTP expiry had the default value (we extended it a bit waiting for our issue to be solved).
The user experience is not great when it takes several minutes to receive the OTP.
We are using Amazon SES with API credentials as an email provider: our SES sending limits are plenty enough to support our current load and send emails in real time. We never reach it.
Could you please DM me the tenant name and sample user address? And in the tenant logs, do you see any delay when Auth0 sends the message to the Custom Email provider?
Sorry about the delayed response. I just sent a DM to you with the details on the tenant logs. The logs do not show there were delays recently. Please let me know if any further queries. Thanks!