I'm using a free-tier compute instances to host a server on Oracle Cloud, but today I accidentally did something with the firewall (either UFW or firewalld, not sure which one) and now SSH-ing gives me an error saying:
ssh: connect to host {the server's ip} port 22: Connection timed out
Rebooting the instance does not help, and I cannot find a way to connect to undo the mistake. I heard someone say you could make a new volume or attach it to a different server, but the issue with that is I have used all the resources in the free tier (aka all RAM, ARM cores, and 200GB for the boot volume), so I would go over the limit and paying is not an option. Nothing I seem to do is working, so if anyone can help me somehow access the terminal on the instance, that would be appreciated. And yes, port 22 is and always has been allowed in the subnet rules. And a (probably) dumb question once this is fixed: is it even needed to have a firewall on the server if there's already one in the security list subnet rules?