Menlo Security incident
An Issue impacting Email is being investigated
Menlo Security experienced a minor incident on September 4, 2026 affecting Global - Email Flow (Global - Email Flow), lasting 5h 33m. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- investigating Sep 04, 2026, 09:33 AM UTC
An issue impacting Email is being investigated. Some customers may see emails rejected by upstream with a 451 error, resulting in delayed emails. Further information and status updates will be shared here as they become available.
- investigating Sep 04, 2026, 09:53 AM UTC
Our engineering teams believe the root cause is the upstream provider not the Menlo service. There are reports of similar errors from multiple sources though no official confirmation yet. Our engineering teams continue to monitor the situation.
- investigating Sep 04, 2026, 10:50 AM UTC
The root cause has been confirmed as the upstream provider not the Menlo service. Some customers will see email delays. Our engineering teams continue to monitor the situation.
- investigating Sep 04, 2026, 12:51 PM UTC
The root cause has been confirmed as the upstream provider not the Menlo service. They have identified the issue and are working on a fix. Some customers will continue to see email delays until the issue is fully resolved. Our engineering teams continue to monitor the situation.
- resolved Sep 04, 2026, 03:06 PM UTC
The upstream provider has implemented a fix and the issue is now resolved. Please contact support if you have additional questions.