not working outside of tmux (probably doing something wrong)

[AdamBD]

This is my installation:

	{
		'declancm/windex.nvim',
		config = function()
			require('windex').setup({
				default_keymaps = false, -- Enable default keymaps.
			})
		end
	},

and my invocation

keymap('n', '<Leader>m', "<Cmd>lua require('windex').toggle_maximize()<CR>", default_opts)

I get this error: Error: Tmux 1.8+ is required. Use 'maximize_nvim_window()' instead or install/update Tmux