Mailgun outage, October 2025: US Email Ingest Errors
Mailgun reported and resolved an incident: US Email Ingest Errors. It lasted 1 minute.
OKResolved
From Mailgun's official status page, in their words.
What happened
- Started
- Resolved
- Duration
- 1 minute
- Impact
- minor
- Investigating
- Identifiednot posted
- Monitoringnot posted
- Resolved
Why it happened
Mailgun has not given a cause in its updates. We never guess one.
How it was resolved
Between 12:55 UTC and 13:07 UTC, customers may have experienced email sending failures in the US region. A deployment of new code caused our sending pipeline to temporarily reject some email submissions with HTTP 500 or SMTP 451 errors (~ 2.5% of requests). Our team quickly identified the issue, rolled back the deployment, and restored normal service. Traffic was immediately shifted from the affected US region to the non impacted region to further mitigate customer impact while the rollback took place.
Timeline
Oldest first, from the first notice to the resolution. From Mailgun's official status page, in their words.
- resolved
Between 12:55 UTC and 13:07 UTC, customers may have experienced email sending failures in the US region. A deployment of new code caused our sending pipeline to temporarily reject some email submissions with HTTP 500 or SMTP 451 errors (~ 2.5% of requests). Our team quickly identified the issue, rolled back the deployment, and restored normal service. Traffic was immediately shifted from the affected US region to the non impacted region to further mitigate customer impact while the rollback took place.
What this means for a business (and what to check now)
- Retry anything that failed during the 1 minute.
- Enter any payments, bookings or jobs you took another way.
- If a deadline fell inside the window, keep this page as your record of the outage.
The full guide: what to do when a service you rely on is down
Other Mailgun incidents
- Route delays in EU Region, resolved after 1.1 hours
- Route delays in EU Region, resolved after 42 minutes
- Route delays in EU Region, resolved after 58 minutes
- EU Messaging Outage, resolved after 17 minutes
- Microsoft Incident Resulting in Delivery Issues to M365, resolved after 34 minutes
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