Cannot remove a line suddenly appeared in the center of pages (only in desktop mode)

I have created a website with one theme. Suddenly there is a small vertical line appearing over all pages. And it is only in desktop mode. You won’t see it in tablet or phone modes. I didn’t change the CSS(not an IT person or front-end developer). It was not initially there. Not sure after which change or how at all it has been created. Cannot remove it now. Any suggestions?


This site will teach you how to build a WordPress website for beginners. We will cover everything from installing WordPress to adding pages, posts, and images to your site. You will learn how to customize your site with themes and plugins, as well as how to market your site online.

Buy WordPress Transfer