Stova's V1 email infrastructure was added to the Spamhaus blocklist (DNSBL), which is used by major recipient mail systems including Microsoft. The affected IP addresses have since been removed from Spamhaus. Recipient mail systems do not query Spamhaus in real time. They cache results, typically for 1-24 hours, with some Microsoft systems taking up to 48 hours. Email delivery will normalise as those caches refresh. Some emails may continue to bounce during this window. We have also submitted direct delisting requests to Microsoft to speed up clearance on their internal blocking systems. We are monitoring V1 deliverability across both NA and APAC servers. The next update will be posted once we see consistent successful delivery, or if anything changes.
Posted May 04, 2026 - 23:50 EDT
Update
We are continuing investigation of an intermittent Email Delivery Issues for Email V1 Clients.
Posted May 04, 2026 - 21:21 EDT
Investigating
We are currently experiencing an intermittent deliverability issue with Email V1 Clients. During this time emails may not be received for some recipients. This will affect Registration, Marketing, Networking & Abstracts. We will provide updates regularly.