Fastmail incident
Replies sent using masked email addresses are bouncing
Resolved after 11 hours 12 minutes, on September 23, 2026.
Our developers have resolved the issue. An update we made wasn't fully applied, causing messages sent from masked email addresses to bounce. If you were affected, you can resend any messages that bounced..
Update timeline
- investigating Sep 23, 2026, 08:00 PM UTC
We're currently experiencing an issue where replies sent from masked email addresses are bouncing with an error instead of being delivered. Our team is investigating the issue. As a workaround, please add the email address you're looking to send emails from under Settings → My email addresses. You'll then be able to send emails from that address..
- identified Sep 24, 2026, 06:48 AM UTC
Our developers have identified the issue and are working towards a fix..
- resolved Sep 24, 2026, 07:12 AM UTC
Our developers have resolved the issue. An update we made wasn't fully applied, causing messages sent from masked email addresses to bounce. If you were affected, you can resend any messages that bounced..
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