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Optimizely: Email Campaign Delivery Drops — NA Region
Optimizely reported a major degradation dropping some email campaign messages in the NA Region from 2026-06-17 14:00 UTC to 2026-06-20 17:41 UTC, lasting 3 days 3 h. Optimizely cited a likely SendGrid header-processing incompatibility and deployed a fix; it lacked records identifying which recipients received messages, complicating decisions about rerunning affected campaigns.
Machine-written from the archived incident (Sol). Check the timeline before relying on it.
Affected components: CampaignsOptimizely Data Platform - NA Region - Campaigns
Timeline of updates
- investigating
We are investigating an issue causing some email campaign messages to be dropped in the North America region. Some emails are still being delivered. Accounts using email campaigns in the region may be affected. We will update as we learn more.
- investigating
We are continuing to investigate this issue. We also have a support thread open with Sendgrid.
- investigating
We are still looking into this issue and will provide updates as they become available.
- identified
We have likely identified the root cause as a recent SendGrid change that introduced an incompatibility in header processing. We are sharing our findings with SendGrid and implementing a workaround to restore compatibility.
- monitoring
We have deployed a fix to unblock affected customers and are actively monitoring the system to confirm stability. We are also working with our email vendor (SendGrid) to put a more complete solution in place on their side. Please note: during the period when emails were partially dropped, we do not have a record of which individual recipients successfully received messages. As a result, if you choose to re-run an affected campaign (e.g., by sending it to a new campaign), some recipients may receive duplicate emails. We will provide a further update as monitoring continues.
- monitoring
We are continuing to monitor for any further issues.
- resolved
This incident has been resolved.
Rewindex changes for this incident
- Major incident: Email Campaign Delivery Drops — NA Region 2026-06-17 14:00 UTC
Impact, status and times are the vendor’s own, as last archived. View on stspg.io (opens in new tab). Optimizely profile · Recent Optimizely incidents · Markdown · JSON