I have 2 servers and I want to make a server cluster. After I click build cluster, it shows ”Configured your cluster! Please wait while all servers restart!” But nothing happened. I still can not transfer my data from two servers

Make sure you either check or uncheck the password box when you get to the obelisk / city terminal.

It's often overlooked by new cluster owners.

I disable the password box and it still unable to find another server

And you show both on the same cluster in the cluster tab? If so, then I would recommend submitting a support email ticket as an employee will need to look at that further.