Blank conversation transcripts

-- query resulting blank conversation transcripts
SELECT *
FROM dbo.Queue_Chat_Details
JOIN dbo.Channels
ON Channels.channel_code = Queue_Chat_Details.channel_code
WHERE session_start_time >= '2021-07-22 12:00:00'
AND session_start_time <= '2021-07-23 00:00:00'
AND name = 'WEB'
AND session_id IS NULL
AND conversation_id NOT IN
(
SELECT conversation_id FROM dbo.pre_chat
);