# RudderStack: Major incident: Ingestion and user transformation timeout issues affecting a subset of the EU customers

**Summary:** RudderStack reported a major EU ingestion and user transformation timeout incident starting 2026-01-28 21:59 UTC, resolved at 22:49 UTC after 50 min. Ingestion returned 5xx errors for some EU customers; SDK retries likely recovered events, but Server Side SDK data loss was possible. Some user transformation executions also timed out. _(machine-written, sol)_
- Kind: Major incident · Label: outage (model (Jev))
- Changed: 2026-01-28 21:59 UTC · Detected: 2026-10-17 18:22 UTC
- [Source: https://stspg.io/n2qf642k9vqw](https://stspg.io/n2qf642k9vqw)
- [Company: RudderStack](https://rewindex.com/company/rudderstack.md)
- Versions: before (none: first archived) → after incident\_version:161/tm6b00ntcpcc@ac380b25bf66
- Change 1 of 1 for this incident

## What changed

**1. Added: Title**

```diff
+ Ingestion and user transformation timeout issues affecting a subset of the EU customers
```

**2. Added: Impact**

```diff
+ major
```

**3. Added: Status**

```diff
+ resolved
```

**4. Added: Start time**

```diff
+ 2026-01-28 21:59 UTC
```

**5. Added: Resolved time**

```diff
+ 2026-01-28 22:49 UTC
```

**6. Added: Affected components**

```diff
+ Data Ingestion - Data Ingestion (EU), Data Ingestion (EU)
```

**7. Added: Update** (identified) · 2026-01-28 21:59 UTC

```diff
+ The issue has been identified and a fix is being implemented.
```

**8. Added: Update** (resolved) · 2026-01-28 22:49 UTC

```diff
+ Between 21:55 - 22:25 UTC RudderStack experienced a temporary ingestion issue which caused 5xx errors on ingestion for a subset of the EU customers. Based on the retry logic of the SDK, these events were likely retried but there might have been some data loss for Server Side SDK's during this timeframe. Also between 21:09 - 22:00 UTC we have observed timeout errors on some of the user transformation code executions that would have dropped the events. We will be running replay for such events wherever data retention is configured
```

## History of this incident

| When (UTC) | Change | Label |
| --- | --- | --- |
| 2026-01-28 21:59 UTC | Major incident: Ingestion and user transformation timeout issues affecting a subset of the EU customers (this change) | outage |

All RudderStack changes: [timeline](https://rewindex.com/company/rudderstack/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/i78cc5bf950884a · Markdown: https://rewindex.com/change/i78cc5bf950884a.md · JSON: https://rewindex.com/api/v1/changes/i78cc5bf950884a · Generated 2026-10-18T02:28:36.692Z