# Sigma Computing: Critical incident: Unable to login and load workbooks for Sigma AWS US

**Summary:** Sigma Computing recorded a critical AWS US outage starting 2023-09-14 18:12 UTC that prevented users from logging in and loading workbooks. The incident lasted 2 h 7 min and was resolved at 2023-09-14 20:19 UTC; engineering implemented mitigation measures, but the root cause was not disclosed. _(machine-written, sol)_
- Kind: Major incident · Label: outage (model (Jev))
- Changed: 2023-09-14 18:12 UTC · Detected: 2026-10-17 18:22 UTC
- [Source: https://stspg.io/jz6vxzdfprwn](https://stspg.io/jz6vxzdfprwn)
- [Company: Sigma Computing](https://rewindex.com/company/sigma-computing.md)
- Versions: before (none: first archived) → after incident\_version:77/wwldjyf7gxln@ed41e3cb5403
- Change 1 of 1 for this incident

## What changed

**1. Added: Title**

```diff
+ Unable to login and load workbooks for Sigma AWS US
```

**2. Added: Impact**

```diff
+ critical
```

**3. Added: Status**

```diff
+ resolved
```

**4. Added: Start time**

```diff
+ 2023-09-14 18:12 UTC
```

**5. Added: Resolved time**

```diff
+ 2023-09-14 20:19 UTC
```

**6. Added: Affected components**

```diff
+ AWS - Sigma - AWS (US), Sigma - AWS (US)
```

**7. Added: Update** (investigating) · 2023-09-14 18:12 UTC

```diff
+ We are investigating an issue with Sigma AWS US users unable to login to the app. We are treating this as our highest priority. Our apologies for any inconvenience caused. Impacted Cloud Regions & Services: Sigma users hosted on AWS US Incident Start Time: Approximately 17:50 UTC September 14, 2023
```

**8. Added: Update** (monitoring) · 2023-09-14 18:59 UTC

```diff
+ Engineering has identified the root cause and implemented mitigation measures. We have confirmed that users are able to login to the app and load Workbooks again. We are continuing to closely monitor. Impacted Cloud Regions & Services: Sigma users hosted on AWS US Incident Start Time: Approximately 17:50 UTC September 14, 2023
```

**9. Added: Update** (resolved) · 2023-09-14 20:19 UTC

```diff
+ The mitigation measures have proven effective, and the issue is resolved. We will perform a root cause analysis (RCA) and publish our findings in a postmortem note to the Sigma Community site in coming days. You will receive a notification when that occurs. Impacted Cloud Regions & Services: Sigma users hosted on AWS US Incident Start Time: Approximately 17:45 UTC September 14, 2023 Incident End Time: Approximately 18:15 UTC September 14, 2023
```

## History of this incident

| When (UTC) | Change | Label |
| --- | --- | --- |
| 2023-09-14 18:12 UTC | Critical incident: Unable to login and load workbooks for Sigma AWS US (this change) | outage |

All Sigma Computing changes: [timeline](https://rewindex.com/company/sigma-computing/changes.md)
_Diff excerpts are shown on normalized text: dates, counters and tokens appear as ‹date›, ‹count›, ‹tok›; noise-only edits are hidden. Rewindex shows the changed passages, not a copy of the page._


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Canonical: https://rewindex.com/change/i6063188db7feac · Markdown: https://rewindex.com/change/i6063188db7feac.md · JSON: https://rewindex.com/api/v1/changes/i6063188db7feac · Generated 2026-10-18T02:31:31.843Z