Substack experienced a notice incident on March 27, 2026 affecting Email delivery, lasting 44d 19h. The incident has been resolved; the full update timeline is below.
Affected components
Email delivery
Update timeline
- investigating Mar 27, 2026, 10:20 PM UTC
We’re investigating an issue affecting reported open rates for some publishers. Current evidence suggests this is related to how Gmail loads tracking pixels, and does not indicate a change in engagement or deliverability. We take responsibility for ensuring these metrics are accurate and are prioritizing improvements to our open rate tracking so this is resolved as quickly as possible. We will continue to provide updates here as we learn more.
- resolved May 11, 2026, 05:55 PM UTC
This incident has been resolved.