Disable Ubuntu default firewall on Oracle Cloud
By default, Ubuntu comes with a firewall called UFW (Uncomplicated Firewall). While it is a useful tool for protecting your system from unauthorized access, sometimes it can cause issues when running certain applications or services.
sudo iptables -F sudo netfilter-persistent save
iptables -F: Flush (remove all) iptables rules
netfilter-persistent save: Save empty ruleset to disk so it will be reloaded on reboot.