Slack error token_expired: Token has expired

The token was valid, but its lifetime ran out. Slack's reference description is simply "Authentication token has expired". You will only ever see this if your app uses expiring credentials — most commonly token rotation, where access tokens are short-lived and must be exchanged for new ones using a refresh token before they lapse. Apps using classic non-expiring tokens never encounter it; if you are seeing it and did not knowingly opt into rotation, some part of your install flow did.

The failure mode is almost always the refresh machinery, not Slack. Typical patterns: the refresh job silently stopped (crashed cron, paused queue), the refresh succeeded but the new token was written to one store while workers read from another, or clock skew let a token be used a few seconds past its expiry under load. Unlike token_revoked this state is self-inflicted and fully recoverable without a human: exchange the refresh token, store the new pair, retry the original call.

Handle it as a one-shot refresh-and-retry: on token_expired, run the refresh exchange, persist atomically, and retry the failed request once. If the refresh itself fails, escalate to the re-install path, because a lapsed refresh token cannot be revived.

{"ok": false, "error": "token_expired"}

Refresh proactively on a schedule comfortably inside the token lifetime rather than reactively on failure, and treat token_expired in production as a signal that the scheduler failed. Keep exactly one writer and one source of truth for the credential pair. If your app has no reason to use rotation, use classic non-expiring bot tokens and this error disappears from your vocabulary.