Degraded performance affecting availability of newly submitted session results in US-East-1

Update timeline

1. investigating Apr 17, 2026, 04:06 PM UTC

   As of 16:00 UTC, we are currently experiencing a slowdown in availability of newly submitted submitted session results in the us-east-1 region. There is no data loss, all saves and submissions are being queued as designed, and the assessments stack remains operational. Delays may currently be experienced using the Data API to fetch session results, and the Reports API to display results. Other workflows that rely on the synchronous use of Data API results may also be affected. Learnosity Support and Systems Engineering teams are actively investigating the issue, and will follow on with an update and resolution as soon as possible.

2. identified Apr 17, 2026, 04:21 PM UTC

   As of 16:20 UTC, Learnosity has increased database performance and we are processing queued sessions rapidly. Learnosity Support and Systems Engineering teams are continuing to actively investigate the issue, and will follow on with an update and resolution as soon as possible.

3. monitoring Apr 17, 2026, 04:28 PM UTC

   As of 16:25 UTC, we have resolved the slowdown in processing session results and all sessions are being scored normally. We will continue to monitor for a further 30 minutes before closing this incident report. Learnosity Support and Systems Engineering teams are continuing to actively investigate the issue, and will follow on with an update and resolution as soon as possible.

4. resolved Apr 17, 2026, 05:58 PM UTC

   As of 16:55 UTC, we are have resolved the degraded performance issue affecting availability of session data in us-east-1. Learnosity Support and Systems Engineering teams will follow up with a post mortem once we have completed root cause analysis and finalized any next steps or preventative measures required. Please reach out if you have any questions or concerns.

5. postmortem May 04, 2026, 05:23 PM UTC

   ### Affected Systems and Regions On 2026-04-17, Learnosity experienced a service degradation impacting availability of newly submitted session results for a small subset of customers in US-East-1. The issue began at approximately 13:54 UTC and was resolved at 16:24 UTC. The total duration of customer impact was approximately 2.5 hours. ### Investigation Service degradation was detected following the accumulation of submitted sessions in the async scoring queue, This was caused by elevated CPU utilization when heavy load coincided with a background data migration task that had been running for several days on the affected EC2 instance. This reduced message processing throughput, leading to queueing of sessions. ### Resolution Learnosity CloudOps engineers responded by scaling session processing node EC2 instances, and corresponding database proxies, to maximum allowable capacity. The migration task was also stopped, which further reduced CPU pressure and allowed message processing throughput to recover. The session scoring backlog was fully cleared by 16:24 UTC. ### Prevention Learnosity is implementing the following measures to mitigate: * Pre-flight health checks and safeguards are being introduced to prevent migration tasks from running during busy periods of production usage. * Enhanced monitoring is being applied to detect backlog growth and database contention, and apply remedial action more quickly