Lettermint incident

Elevated 500 errors with API authentication

Minor Resolved View vendor source →

Lettermint experienced a minor incident on June 26, 2026 affecting Lettermint website and Incoming and 1 more component, lasting —. The incident has been resolved; the full update timeline is below.

Started
Jun 26, 2026, 09:01 PM UTC
Resolved
Jun 26, 2026, 09:01 PM UTC
Duration
Detected by Pingoru
Jun 26, 2026, 09:01 PM UTC

Affected components

Lettermint websiteIncomingTeam APILettermint UISMTP RelaySending APIWebhooks

Update timeline

  1. investigating Jun 26, 2026, 08:56 PM UTC

    Status: Investigating We are investigating an increase in 500 errors. Affected components Lettermint website (Operational) Sending API (Partial outage) Team API (Partial outage) Outgoing (Transactional) (Operational) Outgoing (Broadcast) (Operational) Webhooks (Operational) Lettermint UI (Operational) Incoming (Operational) SMTP Relay (Partial outage)

  2. resolved Jun 26, 2026, 09:01 PM UTC

    Status: Resolved We have resolved the API token authentication issue as of 23:01 CEST by rolling back the change that introduced the failure. Between approximately 22:56 and 23:01 CEST, a subset of API requests using tokens may have failed when they required a fresh authentication lookup. Requests using already-cached token authentication continued to work. We are treating this as a high-priority reliability incident. Given the recent increase in production incidents, we are pausing this rollout path and tightening our migration and deployment safeguards before reintroducing the change. All affected services are currently operating normally. Affected components Lettermint website (Operational) Team API (Operational) SMTP Relay (Operational) Outgoing (Broadcast) (Operational) Webhooks (Operational) Lettermint UI (Operational) Sending API (Operational) Outgoing (Transactional) (Operational) Incoming (Operational)