A configuration issue caused instability for sending and receiving email. The issue was resolved a few minutes ago and the system was affected for almost an hour, from 09:30 AM UTC to 10:30 AM UTC. That's 05:30 AM to 06:30 AM New York time. Any mail that arrived during the instability should get retried or delivered soon if it hasn't already. If you were not able to send an email, then you can try again now and it should work. We're sorry for the inconvenience!