SMTP delays for some SparkPost and SparkPost Enterprise customers (US hosted only)

Incident Report for SparkPost

Resolved

Deliveries continue to be normal. If there is any queued mail due to the incident it will be delivered shortly.
Posted Mar 30, 2018 - 20:54 EDT

Monitoring

We are seeing significant improvement but are continuing to monitor as queues drain. Once again, apologies for the inconvenience.
Posted Mar 30, 2018 - 20:11 EDT

Update

Brief Update: We have made some progress and mail delivery rates are improving, we expect this to continue. We will post a further update in due course.
Posted Mar 30, 2018 - 19:12 EDT

Identified

We have identified the issue and are taking steps to mitigate this, while working on a longer term solution with our partner.
We will continue to post updates as the solution progresses, apologies once again for the impact to your businesses.
Posted Mar 30, 2018 - 16:55 EDT

Investigating

We are investigating delays for some sending IP addresses with a message of "421 4.4.0 [internal] no mail servers for this domain could be reached at this time"
Posted Mar 30, 2018 - 14:31 EDT
This incident affected: SMTP Delivery (Outbound Message Delivery) (SMTP Delivery - USA).