Does the pop-up usually say something along the lines of "You are randomly picked for a new iphone 7!" or "You have won a free spin?" Then, we have the same problem. I have an iphone also, and what I just do is click the blue cancel button at the end of the pop-up and just ignore it until I finish the manga that im reading. If it redirects you to another website, you can just block the website by going to your retrictions on settings, go to websites, and click on 'limit adult websites' which would give you the option of blocking the websites. You'd still be able to go on different websites, you'd just need to enter your restriction password.
This pop up ad keeps coming up and won't let me read my manga. Saying something about updating the android but I have an iPhone??? Is anyone else having this same problem