2050: Reaction target not ready.

HTTP status: 422.

The reaction part’s message_id names a message this API accepted but the channel has not yet acknowledged, so a reaction cannot be addressed to it. Nothing was sent.

• Read the target message until its status is sent (its channel_message_id appears at the same moment), then resend the reaction. message.sent is journaled when the send is accepted, not when the channel acknowledges it, so it is not the signal to wait for.