As asked during the install process you are supposed to add a subdomain for the panel login. This is the proper way to install. There should not be a sentora/panel/panel/ folder. Best idea is to re-install minimal OS and re-run the install script and answer all the questions.
The panel login should be something like panel.alphas.sx or cp.alphas.sx or whatever you choose.
The panel login should be something like panel.alphas.sx or cp.alphas.sx or whatever you choose.