We have corrected the configuration, and external tests confirm that emails should now be delivered successfully again.

If you believe any email messages have been rejected during this period, please re-send them (For example, for a Mobile Credential, please re-issue the credential).

The issue has been identified as related to a configuration change made on September 27th, the effect of which would cause some downstream email servers to reject emails as spam. We are working to correct the configuration.