Getting Access Denied error

I am trying out shiny pro trail version on my private cloud and I am facing the following issue. Can someone help?

I want to understand if any shiny files will be created on the server to make sure I provide proper permissions before spinning up docker container.

[INFO] shiny-server - Using config file "/etc/shiny-server/shiny-server.conf"
[INFO] shiny-server - Creating user-specific config directory at /.shiny-server
  return binding.mkdir(pathModule._makeLong(path),
Error: EACCES: permission denied, mkdir '/.shiny-server'
    at Error (native)
    at Object.fs.mkdirSync (fs.js:923:18)
    at n (/opt/shiny-server/main.min.js:107:474)
    at d.modules.Ng.$init (/opt/shiny-server/main.min.js:114:399)
    at new d (/opt/shiny-server/main.min.js:110:352)
    at /opt/shiny-server/main.min.js:355:494
    at Object.<anonymous> (/opt/shiny-server/main.min.js:366:225)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)

I have figured out how to resolve the issue. the folder is getting created on current work directory. I changed and it got resolved.

Now, I am facing below issue

[ERROR] shiny-server - Error loading config: The user 'undefined' does not have permissions to run applications as one of the users in 'shiny'. Please restart shiny-server as one of the users in  'shiny'. (/etc/shiny-server/shiny-server.conf:2:1)