Changes / Optimizely / Email Campaign Delivery Drops — NA Region
Optimizely: Major incident: Email Campaign Delivery Drops — NA Region
Summary
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 diff below (Sol; type: incident degradation). Check the diff before relying on it.
Major incidentLabel: degradation (model (Jev), 76%)Changed Detected Source: stspg.io (opens in new tab)
What changed
Before: not present
After: Email Campaign Delivery Drops — NA Region
Before: not present
After: major
Before: not present
After: resolved
Before: not present
After: 2026-06-17 14:00 UTC
Before: not present
After: 2026-06-20 17:41 UTC
Before: not present
After: Campaigns, Optimizely Data Platform - NA Region - Campaigns
Before: not present
After: 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.
Before: not present
After: We are continuing to investigate this issue. We also have a support thread open with Sendgrid.
Before: not present
After: We are still looking into this issue and will provide updates as they become available.
Before: not present
After: 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.
Before: not present
After: 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.
Before: not present
After: We are continuing to monitor for any further issues.
Before: not present
After: This incident has been resolved.
First version of this incident archived by Rewindex. View the live incident (opens in new tab).
History of this incident
| When (UTC) | Change | Kind |
|---|---|---|
| Major incident: Email Campaign Delivery Drops — NA Region (this change) 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. | Major incident |
All Optimizely changes → · Optimizely profile · Markdown · JSON