not able to create folder inside a folder using CSOM

Question

I am trying to create a folder inside a folder

The parent folder is inside a document library

Below is my code

List<Folder> Affaires = GetAllFolders(oWeb.Lists.GetByTitle(LibraryName));
                    foreach(Folder Affaire in Affaires)
                    {
                        try
                        {
                            Folder folder = ctx.Web.GetFolderByServerRelativeUrl(Affaire.ServerRelativeUrl + "/Mails");
                            ctx.Load(folder);
                            ctx.ExecuteQuery();
                            Folder Sample = Affaire.Folders.Add("Sample");
                            //it goes to catch block after the below statement
                            ctx.ExecuteQuery();
                        }
                        catch (Exception ex)
                        {
                            Console.WriteLine("");
                        }
}

I also tried

    Folder folder = ctx.Web.GetFolderByServerRelativeUrl("Site-580515/Affaires/Test Affaire");
                                ctx.Load(folder);
                                ctx.ExecuteQuery();
                               //it runs till next line
                                folder.Folders.Add("Demo");
                                ctx.ExecuteQuery();

Answer 1

var list = ctx.GetListByTitle("MyList);
list.EnableFolderCreation = true;
list.RootFolder.EnsureFolder("Folder1").EnsureFolder("SubFolderToFolder1");
ctx.ExecuteQuery();

This will create "Folder1" and subfolder "SubfolderToFolder1" if they do not exist.

Answer 2

List list = web.Lists.GetByTitle("listName");

clientContext.Load(list.RootFolder.Folders);

clientContext.ExecuteQuery();

foreach (Folder subFolder in list.RootFolder.Folders )

    {

        if (subFolder.Name != "Forms")

        {
            var newFolder = subFolder.Folders.Add(folderName);

            newFolder.Update();

            clientContext.ExecuteQuery();

            Console.WriteLine("Folder Created in Subfolder:" + subFolder.Name);
        
        }
    }