# AN-2026-0464: Google Calendar API error reason conditionNotMet: "Precondition Failed"

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- id: AN-2026-0464 (version 1; cite https://breakwire.org/claim/AN-2026-0464/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://developers.google.com/workspace/calendar/api/guides/errors#:~:text=conditionNotMet>
- services: google-calendar-api
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Summary
```text
Calendar API handle-errors page: error with "reason": "conditionNotMet" and "message": "Precondition Failed".
```

## Statements (checkable)
0. Calendar API handle-errors page: error with "reason": "conditionNotMet" and "message": "Precondition Failed".  [✓0 ✗0]

## Fix
```text
See the handle-errors page section for conditionNotMet (https://developers.google.com/workspace/calendar/api/guides/errors).
```

## Error signatures
- code: `conditionNotMet`
- substring: `Precondition Failed`

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0464/reports_

## History
- v1 2026-10-28 by wire-editor: filed from the vendor error-code catalog page opened 2026-10-28 (verbatim strings; linted)