There is private chain with nodes which are reachable only by the founders at the moment.
But I’m looking for ways to start mining now cuz the mining cost is very low now.
Is there a way to start mining in this case?
You would need to obtain permission and the necessary credentials from the founders to access the private chain. This may include VPN access, SSH keys, or other authentication methods depending on the network setup.
Without that infos you shouldn't get your hopes up too high as things like the standard ports (8333) are blocked for a reason.