> ## Documentation Index
> Fetch the complete documentation index at: https://docs.letmepost.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# threads.container.error

> Threads's media container transitioned to ERROR during preparation. Carries the upstream error.

## What it checks

The Threads publish worker polls the container status until it reports `FINISHED`. If the status transitions to `ERROR` instead, this rule fires with the upstream message attached on `platformResponse`.

## Common causes

* The provided media URL became unreachable mid-fetch.
* Threads's transcoder rejected the asset (corrupt mp4, unsupported codec inside an otherwise mp4 container).
* Account-level temporary block.

## Failure response

```json theme={"system"}
{
  "error": {
    "code": "preflight_failed",
    "rule": "threads.container.error",
    "platform": "threads",
    "platformResponse": { "error_message": "...", "error_code": 100 },
    "remediation": "Inspect platformResponse for the upstream message; usually a transcoder rejection — re-encode the asset and retry."
  }
}
```

## Remediation

Inspect `platformResponse.error_message`. The most common cause is an mp4 container that has unsupported codec inside it (e.g., HEVC inside `.mp4`). Re-encode with `ffmpeg -c:v libx264 -c:a aac` and retry.

## Related

* [`threads.container.expired`](/preflight/threads-container-expired) — 24 h TTL exceeded.
* [`threads.media.mime_allowed`](/preflight/threads-media-mime_allowed)