First, you need to set "RewriteLogLevel 9" to turn on rewrite log for that vhost.
Next, clicking "Enable debug logging" from LSWS control panel, to turn on debug logging, click again will turn it off.
Go to your site and click around, until you produce a few 404 pages, turn dbug logging off. then send lsws/logs/error.log to bug ((a)) litespeedtech ((.)) com.