Why is my phone asking for installation of random apps?

[Android Central Question]

Hi,
I have the Samsung Galaxy S8+ which I just bought 2 days ago.
since the first day, I've started getting a message from my phone for the installation of an app called "reader" version "A18". The message says "this app may be harmful to your phone or data, installation is not recommended". The message has to options "cancel" or "install".
I always press cancel and still get the message once or twice a day. I have cleared all browsing data for Chrome and disabled it's permission for storage, and i have also uninstalled Samsung internet. I'm still not sure why I'm getting this message every day, I have no suspicious apps installed too, they're all Google play verified. Does anyone have a solution to this? It would be really appreciated.

 

[B. Diddy]

Welcome to Android Central! Does this only appear when you're browsing, or does it also appear when you're on the homescreen, or using some other app?

 

[huzaifa792]

B. Diddy,
this happens at random times, while on the homescreen, using instagram, browsing, it just happens randomly.

 

[B. Diddy]

See if this guide helps: https://forums.androidcentral.com/a.../901497-full-screen-ads-how-find-culprit.html. Also, does it help if you turn off the Unknown Sources option in the security settings?