# Klaviyo: Major incident: Elevated errors for SMS opt-ins, scheduling, and sending

**Summary:** Klaviyo reported a major incident affecting SMS subscriptions, delaying SMS sends, and causing errors creating or scheduling SMS and WhatsApp campaigns. It started at 2026-07-21 20:36 UTC and was resolved at 2026-07-21 21:09 UTC, lasting 32 min. Klaviyo implemented a fix but did not disclose the cause. _(machine-written, sol)_
- Kind: Major incident · Label: outage (model (Jev))
- Changed: 2026-07-21 20:36 UTC · Detected: 2026-10-17 18:22 UTC
- [Source: https://stspg.io/wdqtkt49pl9x](https://stspg.io/wdqtkt49pl9x)
- [Company: Klaviyo](https://rewindex.com/company/klaviyo.md)
- Versions: before (none: first archived) → after incident\_version:249/lmb1bgttxw5x@2926dbdd7114
- Change 1 of 1 for this incident

## What changed

**1. Added: Title**

```diff
+ Elevated errors for SMS opt-ins, scheduling, and sending
```

**2. Added: Impact**

```diff
+ major
```

**3. Added: Status**

```diff
+ resolved
```

**4. Added: Start time**

```diff
+ 2026-07-21 20:36 UTC
```

**5. Added: Resolved time**

```diff
+ 2026-07-21 21:09 UTC
```

**6. Added: Affected components**

```diff
+ Campaigns - Text Message Sending, Campaigns - WhatsApp Sending, Text Message Sending, WhatsApp Sending
```

**7. Added: Update** (investigating) · 2026-07-21 20:36 UTC

```diff
+ We are currently investigating an issue impacting SMS subscriptions, delays in SMS sending, and errors when creating or scheduling SMS and WhatsApp campaigns. We are working to restore normal service as quickly as possible. We will share another update as soon as we have more information.
```

**8. Added: Update** (identified) · 2026-07-21 20:47 UTC

```diff
+ We have identified the cause of the issue and a fix has been implemented. We are starting to see improvements in system performance.
```

**9. Added: Update** (monitoring) · 2026-07-21 20:57 UTC

```diff
+ System performance for SMS opt-in forms, sending, and campaign creation and scheduling remains stable. We continue to monitor closely and appreciate your patience throughout this incident.
```

**10. Added: Update** (resolved) · 2026-07-21 21:09 UTC

```diff
+ SMS subscriptions, SMS sending, and the creation and scheduling of SMS and WhatsApp campaigns are operating as expected. This incident has been resolved.
```

## History of this incident

| When (UTC) | Change | Label |
| --- | --- | --- |
| 2026-07-21 20:36 UTC | Major incident: Elevated errors for SMS opt-ins, scheduling, and sending (this change) | outage |

All Klaviyo changes: [timeline](https://rewindex.com/company/klaviyo/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/ieecbe5e346cf71 · Markdown: https://rewindex.com/change/ieecbe5e346cf71.md · JSON: https://rewindex.com/api/v1/changes/ieecbe5e346cf71 · Generated 2026-10-18T00:52:45.518Z