The mail queues are now substantially better and mail delivery is happening normally. Sending servers at other email services will retry sending messages you have not received if they haven't already returned the messages to the sender. You may still see some message you expected earlier to arrive over the next few hours.

Further investigations into the remaining email delivery issues revealed a lingering block by certain DNS servers, which caused problems delivering email to services using those nameservers. A workaround to circumvent this problem appears to be working and the outgoing email queue to the affected services is decreasing.

The cascading issues with incoming and outgoing email delivery have substantially improved and continue to subside, but any delayed or incorrectly rejected messages are problematic and we are continuing to address this with our system administration team.

It appears that a a result of the DDoS (Distributed Denial of Service) attack a couple of days ago some of the mitigations put in place are affecting the ability of our servers to find DNS details for the domains that emails are delivered to. This is also affecting some incoming mail.

Most messages appear to be being delivered normally, but some are being affected by this issue and we are continuing to work on this.

The same issue is also affecting our system's ability to validate new customer domains when they add them to their accounts. If you think this is affecting your domain please email mail@support.runbox.com and we can look in to this for you.

We are currently looking in to a possible issue with outgoing mail delivery being delayed.