title: Get a subfolder using SharePoint CSOM
body: <p>I am wanting to get a folder within Shared Documents on a SharePoint site using CSOM in order to add files to it.
  Here is my current code:</p>
  
  <pre><code>        // Get the folder we want to add images to
          var context = new ClientContext(sharePointSiteUrl)
          context.Credentials = new SharePointOnlineCredentials(username, password);
          Web web = context.Web;
          Folder targetFolder = web.GetFolderByServerRelativeUrl("/Shared%20Documents/" + nameOfTargerFolder);
          context.ExecuteQuery();
  </code></pre>
  
  <p>And I am getting this error: "Server relative urls must start with SPWeb.ServerRelativeUrl"</p>
  
  <p>Thanks so much!</p>