You can try to recheck if you have properly selected the wide format for default layout, pages and posts. If all are selected as wide format, you can check the individual posts or pages if they’re layout are accidentally set differently (layout options selected on each page/post override the general design settings of the theme). If you’re still having trouble, you can also try to check your widgets and try removing those that are located on the right sidebar.
Hope this will help you. If not, then I’m sure someone else here will be able to. ??