Steps to reproduce the problem:
1. browsing webpages
2. waiting for the issue to come
3. happens several times a day

What is the expected behavior?
This is not an ad comming from the webpage I am looking at. Pop up windows are blocked in chrome configuration, it still hapens.

What went wrong?
I did not root my phone nor did I install app outside the play store. So I dont think I brought a virus on my phone. The scam ad can not comme from the website I ma surfing on. The fact that suddenly chrome is showing that type of malware ad makes me think something might be wrong with chrome security.

Did this work before? N/A 

Chrome version: 56.0.2924.87  Channel: stable
OS Version: 7.0
Flash Version: Shockwave Flash 24.0 r0

I don't know if this is the right place to mention that issue, the fact that it still happens just after a factory reset of my phone makes me think it might be a security issue. I did not find anything on that topic. Thank you. Best regards