If iptables is not sending LOG messages to the syslog file, there are a few things you can try:
Make sure that the kern.info facility is configured to log to a file. In most Linux distributions, the kern.info facility is configured to log to the /var/log/kern.log file by default. You can check the syslog configuration to make sure that this is the case.
Check the iptables rules to make sure that the LOG target is being used correctly. The LOG target sends messages to the kern.info facility, so you should make sure that the LOG target is being used in a rule that is being matched.
Check the syslog file to see if there are any errors or messages related to iptables. If there are any errors or messages, they may provide clues about what is causing the problem.
Try restarting the syslog daemon. If the syslog daemon is not running or is not configured correctly, it may prevent iptables from sending LOG messages to the syslog file.
Make sure that the iptables service is running. If the iptables service is not running, it will not be able to send LOG messages to the syslog file.
If none of these solutions work, you may need to troubleshoot the problem further by checking the system logs, configuration files, and other relevant system resources. It's also possible that there is a bug in the iptables software or a problem with the system that is preventing the LOG messages from being sent to the syslog file.