This issue is now resolved. All affected messages were queued and are in the process of being delivered. Thank you for your patience, we apologize for any inconvenience.
We’ve had reports from some accounts that outbound email messages are not being delivered this morning. Our engineers are looking into the problem and troubleshooting what is happening with our mail gateway. For accounts having this problem, messages sent via Custom SMTP are being delivered properly. If you’re experiencing email deliverability issues this morning, please set up a Custom SMTP connection to route messages through your mail server as a work around for this issue.