LINE error 400: Invalid audience group id

A narrowcast (or audience-management) request referenced an audienceGroupId LINE can't use, and the documented example body echoes the offending value: {"message": "Invalid audience group id: {audience ID}"}. The narrowcast error table explains the two flavors: "an invalid audience is specified, such as a status other than READY," or the ID simply doesn't exist in this channel.

The status detail is the interesting one. Audiences are built asynchronously: after you create one and upload user IDs, the audience passes through processing states before reaching READY, and only a READY audience can be targeted by a narrowcast. Click and impression audiences also need their source data to be old enough to have accumulated, and audiences can end up in failed or expired states. So "the audience exists in the console" is not the same as "the audience is usable right now" - your send pipeline has to check audienceGroupStatus via the get-audience-data endpoint before referencing the ID (size floors then apply separately - see Not enough recipients).

Scoping applies as everywhere on this API: audience IDs belong to the channel (or are shared into it via Business Manager); an ID from another channel or environment is invalid here. And because up to 1,000 audiences can exist per channel, stale IDs from deleted audiences linger in config files long after the audience itself is gone.

// If you specify an invalid audience ID (400 Bad Request)
{
    "message": "Invalid audience group id: 1234567890123"
}

Gate every narrowcast on a pre-flight audience check (status == READY, expected size present) instead of trusting stored IDs. Keep audience IDs in the same environment-scoped config as channel credentials so cross-environment reuse is impossible, and clean up config when audiences are deleted - the 1,000-audience cap makes periodic pruning necessary anyway. See audience limits.