Service Issue: Outbound sending seeing high bounce rates from Spamhaus

After 51 minutes

Bounces rates have normalized and we are not seeing any lingering Spamhaus issues. We will continue to monitor.

After 33 minutes

We are seeing bounce rates return to normal levels and the effect of this Spamhaus issue decreasing quickly.

After 9 minutes

We have learned that this is a global issue with Spamhaus and not specific to Postmark. We are still not seeing any on our IP's blacklisted will continue to update here as bounces subside.


We are looking into an increase in bounces from Spamhaus. Our IPs are Not listed on this blacklist provider so we are continuing to investigate a root cause.

Began at:

Affected components
  • API
  • SMTP (sending)