platform_rejected

​

What triggers it

• A platform rule we don’t yet enforce locally — e.g., a content moderation rejection, an account-state issue (rate-limited at the platform level, suspended), or a constraint introduced after our last update.
• An async media-validation failure on Meta’s container flow (the file passed our size + mime checks but failed deeper inspection).
• A platform-specific rejection we haven’t translated into a preflight rule yet.

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Response shape

{
  "error": {
    "code": "platform_rejected",
    "message": "Threads rejected the create-container call: media URL not reachable.",
    "rule": "threads.container.error",
    "platform": "threads",
    "platformVersion": "graph-2026-04",
    "platformResponse": {
      "error": {
        "message": "Container creation failed",
        "code": 100,
        "fbtrace_id": "..."
      }
    },
    "remediation": "Verify the media URL returns 200 anonymously, or upload via POST /v1/media first.",
    "docUrl": "https://docs.letmepost.dev/errors/platform_rejected",
    "ruleUrl": "https://docs.letmepost.dev/preflight/threads-container-error",
    "requestId": "req_..."
  }
}

​

How to handle

1. Inspect platformResponse for the upstream code / subcode.
2. If it’s a known opaque rejection (e.g., Instagram’s OAuthException 2207052), check the matching preflight rule page and follow the remediation there.
3. File an issue: every platform_rejected we see in production is a candidate for a new preflight rule. The dashboard’s post log makes these easy to spot.

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HTTP status

• 4xx (the platform’s status, passed through) when the upstream said the call is invalid.
• 502 Bad Gateway when the upstream returned a 5xx — we map upstream 5xx to our 502 + platform_unavailable instead of platform_rejected. See platform_unavailable for that case.

​

Related

• platform_unavailable — upstream returned 5xx; transient.
• preflight_failed — we caught it before the platform did.