Email Security delivery impacted by Spamhaus listing
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Email Security delivery impacted by Spamhaus listing Cloudflare operates global DNS, CDN, WAF, and edge network services. Outages here often affect many sites and APIs that sit behind their network.
resolved · 12 Aug 2026, 17:23 UTC
This incident is now resolved.
monitoring · 12 Aug 2026, 16:48 UTC
All IPs previously listed by Spamhaus are now clean. Monitoring the propagation of that change to downstream systems.
investigating · 12 Aug 2026, 16:30 UTC
We are continuing to investigate this issue. Customers using O365 will be impacted only if they have not completed the required setup. Please check your setup and ensure the connector includes all egress IPs: https://developers.cloudflare.com/cloudflare-one/email-security/setup/pre-delivery-deployment/prerequisites/m365-email-security-mx/#2-configure-enhanced-filtering
investigating · 12 Aug 2026, 15:07 UTC
We are continuing to investigate this issue.
investigating · 12 Aug 2026, 15:04 UTC
We are currently investigating an issue where customers that use Spamhaus for additional filtering of email downstream from the Cloudflare Email Security service are rejecting emails from IPs in the 134.195.26.0/23 block. This IP block should be allowed for all customer downstream systems to avoid treating the Email Security service as an originator of mail. We recommend all Cloudflare Email Security customers disable Spamhaus filtering in downstream systems.
5
Related incidents
2h 19m
This incident
51m
Avg. resolution time
Slower
vs. average
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