Thanks, Ying! It worked but now I am having trouble with the customizer. When editing the sidebars, the customizer is working only for the home page and individual post page but not on the category archive page.
The home page and individual post page should be with sidebars, but the category archive should be without a sidebar to make it look more spacious as there are 4 posts displayed in columns for each archive category page. Please help. Thanks.