I have this issue so bad that it happens every 5 minutes. Galaxy S4. It started yesterday. I have not downloaded ANY APPS RECENTLY. I have found several people online that show a fix, but it does not work. Clearing data in browser, master reset, uninstall all apps, does nothing. Avast! And lookout both say my phone is fine.
I will be buying an iphone in less than a week if I don't find an answer. And I have owned over 10 androids. But never again after this. The lotto scam has rendered my phone halfway unuseable. I am distantly selecting all and copying in case I lose this entire message now.
Also, chrome does not have a feature to block sites. That would be nice if I could just add all the links to a list my browser would never go to, but this would be too easy.