If you are seeing this in Chrome, it means that there's a possibility a website isn't secure and that you shouldn't enter personal info on it. You shouldn't be doing this on any site with public Wi-Fi anyway. Sometimes this warning pops up on a site you still want to visit but not fill out anything. There should be a box you can tap on that warning screen for "advanced" (or something similar, it's rare that I see this and working off memory). Tap that and you should get an option to navigate to the site anyway.