SIP Service Incident - April 13, 2026
Description of the Issue: On April 13, from 15:56 UTC to 17:14 UTC, some inbound SIP calls experienced failures immediately upon initiation, preventing calls from being completed successfully.
Root Cause: A recent update to our SIP service introduced a race condition between two internal services which resulted in call failures for some customers during the rollout of the upgrade.
Timeline & Actions Taken: Upon detection at 15:56 UTC, our progressive rollout and alerting systems triggered remediation. The canary stage contained the blast radius, preventing the issue from reaching a broader rollout. The incident was fully resolved by 17:14 UTC.
Preventative Actions & Learnings: While our progressive rollout process contained the impact as designed, we are expanding test coverage for service changes and strengthening alerting to reduce time to detection. We are also enhancing inbound call alerting to more proactively surface anomalies in call handling. Finally, we are investing in improved handling of timing-sensitive interactions within our service update pipeline, ensuring changes are validated before reaching any rollout stage.
