Messenger error 200: pages_messaging not reviewed - app not live

Code 200 is the App Review wall, and its message is unusually explicit: "Cannot message users who are not admins, developers or testers of the app until pages_messaging permission is reviewed and the app is live." Meta's error-handling guide files the whole 200-299 block under permission errors, and this is the member every Messenger developer meets on the way to production.

The mechanics: while an app is in Development mode, or Live with only Standard Access to pages_messaging, the Send API works exclusively for people who hold a role on the app (admin, developer, tester). Everything looks perfect in your own testing, then the first real user gets silence. That works-for-me-only signature is the fastest way to recognize 200 without even reading logs, and it is the single most common "my bot ignores everyone else" cause in the Messenger troubleshooting guide.

Two switches must both be flipped: the app toggled to Live mode, and pages_messaging granted Advanced Access through App Review. A Live app with Standard Access behaves, for messaging, exactly as if it were still in development. The review itself wants evidence: reviewers follow your instructions against the real bot, so a test Page, clear steps and a screencast of the end-to-end flow materially speed approval.

Watch the subcode, because code 200 is a family: subcode 1545041 is not a review problem at all but an unreachable recipient, and 2018027 is the same review wall for the separate pages_messaging_phone_number permission. A missing scope on the token, rather than a missing review, surfaces as 230 instead. What is NOT wrong: your token (it authenticated), your code, and the recipient; the gap is administrative.

{
  "error": {
    "message": "(#200) Cannot message users who are not admins, developers or testers of the app until pages_messaging permission is reviewed and the app is live.",
    "type": "OAuthException",
    "code": 200,
    "fbtrace_id": "BLBz/WZt8dN"
  }
}

Put App Review on the launch checklist as a dependency with lead time, not a formality: prepare the reviewer walkthrough while the bot is being built, and verify Advanced Access before announcing the Messenger channel. After any app migration, re-confirm review status before cutover. A synthetic end-to-end test from an account with no app role is the only monitoring that catches this class of failure, because every internal account is exempt from it.