I have Norton Android mobile phone security. When scanned, no virus or malware detected. However, I frequently get gestyy.com popping up, sometimes together with unsolicited advertisements. Why isn't my Norton protection preventing this happening? What action, if any, can I take?
These popups and redirects are often caused by malformed ads on web sites you are visiting. Norton does not block redirects because there are many sites that use them for legitimate purposes, including Norton themselves.
What you should try is installing an ad blocker app/extension for your browsers. One of these usually stops the kind of behaviour you describe.