# 72004: LiveSync connector could not identify target channel Identifier: `livesync_no_channel_key` A LiveSync database connector read a change but could not determine which channel to publish it to, because the change had no _ablyChannel field. Only changes that specify a channel can be published. ## What you should do Make sure each change carries an `_ablyChannel` field naming the channel to publish to, at the top level of the change event rather than nested inside the document. This is normally set by the connector's [aggregation pipeline](https://ably.com/docs/livesync/mongodb.md). ## Why it happens The connector read a change that had no `_ablyChannel` field, so it could not tell which channel to publish it to. Only changes that carry a channel name in `_ablyChannel` can be published, and the field has to be at the root of the change event, not under a nested document. ## What you'll see The error is reported with code 72004 and HTTP status 400. The message is of the form `no channel key in message `.