Now inside the UI I am adding the external storage strange i am able to add the first folder 1 not the folder2 I get error local storage path does not exist. How can i add it
You need to make sure that the user, under which the web server is running (maybe wwwrun or www-data, etc.), is able to access all files and folders. I would recommend to run this check on the console by switch to the user and accessing the file structure.