Mailgun outage, July 2025: HTTPS Tracking Certificate Creation / Renewal blocked by Let's Encrypt Outage

Mailgun reported and resolved an incident: HTTPS Tracking Certificate Creation / Renewal blocked by Let's Encrypt Outage. It lasted 11.6 hours.

Resolved

From Mailgun's official status page, in their words.

What happened

Started
Resolved
Duration
11.6 hours
Impact
minor
Affected
API
  1. Investigating
  2. Identified
  3. Monitoring
  4. Resolved

Why it happened

Mailgun has not given a cause in its updates. We never guess one.

How it was resolved

Mailgun marked it resolved at 22 July 2025, 9:33 pm without a written explanation of the fix.

This incident on the Mailgun status page

Timeline

Oldest first, from the first notice to the resolution. From Mailgun's official status page, in their words.

  1. identified

    Let's Encrypt, the certificate issuer used for creating certificates on customer tracking domains is experiencing an outage (https://letsencrypt.status.io/). Attempting to generate or regenerate a tracking certificate will not succeed until service is restored.

  2. monitoring

    The current status of Let's Encrypt infrastucture is "[Identified] We have deployed mitigations for the failure of our internal DNS servers. Issuance of certificates is now succeeding, though we are still recovering from the resulting high traffic volumes." We are monitoring the situation and will update our status page accordingly.

  3. resolved

    This incident has been resolved.

What this means for a business (and what to check now)

  • Retry anything that failed during the 11.6 hours.
  • 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

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