Help needed! How does automatic_installation work?

[mianm12]

Hi, guys
I am a complete beginner with neovim., just set up my configuration. According to the mason-lspconfig documentation, when automatic_installation is enabled, it will automatically install the servers that are set up via lspconfig. Here is how I set up in my configuration

return {
  "neovim/nvim-lspconfig",
  event = "VimEnter",
  dependencies = {
    "williamboman/mason.nvim",
    {
      "williamboman/mason-lspconfig.nvim",
      opts = { automatic_installation = true, },
    },

    "folke/neodev.nvim",
  },
  config = function()
    ...
    local = servers = {
      lua_ls = {...},
      clangd = {...}.
    }
    local have_mason, mlsp = pcall(require, "mason-lspconfig")
    ...
    if have_mason then
      mlsp.setup({
        handlers = {
          function(server_name)
            local server_opts = servers[server_name] or {}
            server_opts.capabilities = vim.tbl_deep_extend("force", {}, capabilities, server_opts.capabilities or {})
            require("lspconfig")[server_name].setup(server_opts)
          end,
        },
      })
    end
  end,
}

I thought mason-lspconfig would automatically detect the servers configured in lspconfig and then install them. However, it is not working. Did I do something wrong, or did I misunderstand its functionality?