Coming Soon Mode not working

Did activate coming soon mode at the WP but the site still showing the regular page. Try it a few times but no avail. WP Super Cach is activated. Any suggestion as of how to fix it. Is it a server problem or WP problem. For some reason when I view the site on my smart phone, the coming soon mode page is active. However, if I view it on the computer, the page is a regular page.