I have tried EVERY "solution" on this thread. NONE OF THEM WORK. This started for me after the last AT&T/SAMSUNG update to my S8. I have opted out of everything possible. This is a SAMSUNG/CARRIER issue, I don't care what anyone else says. I have used Samsung Android phones for years and have NEVER had this issue until this last "update". Between Google, Twitter, Facebook, etc. selling us out. I have just about had it with all the major manufactures. The OnePlus 6T will be my next phone. No Google, Facebook, etc., unlocked, and completely free of bloatware...BY FALICIA!!!!
It could be malware. If you go to settings, then apps and you scroll down to the end, you may see 2 or 3 apps with no names or icons. Those are malware apps. You can uninstall them for yourself but i downloaded malwarebytes from play store just in case and they took care of it for me. You can click free trial to use the app just for this instance and uninstall it after if you want, or keep it and pay for it after the trial is over.
Hope it helps.
I was able to take a screenshot of mine doing exactly the same thing the difference was when I checked on adchoice up in top it said Google was doing it and I turned it off so I will see if it keeps doing it but it did not start doing it until I installed a GO Keyboard Theme other than the one that I use normally. I deleted these themes and it's still not working not to mention there's nothing in my apps that shows an unwanted app or a non sanctioned app on this phone
I start having the full screen ads everywahre every 2 minuts after getting the securty patch of April. In task screen the ads show that its from playstore. I Tried everything, deleted Apps, used SD mate, AirPush detector etc etc but nothing working and ads still showing and bugging.
Does this still happen when your device is in safe mode?
I too kept getting pop up adds and it's frustrating. Worked ok in safe mode but normal mode kept having ads. I'm using a Samsung note 8 and recently had an update from Samsung. I had already removed all new apps but still got ads. i then clicked on an add and managed to get a screen up to remove the adds. I'll try attach a picture of the link but before you need your imei number by calling *#06# log your imei number than go to the link to opt out. I was sceptical but thought I have an add problem so it can't make it worse so i put my imei number in and no more ads. So far so good it's worked.
Edited: click this link to opt out of adds
The video doesnt work, never worked, not sure why it is the solution. Clear All Cached Data
From a Home screen, touch and swipe up or down to display all apps.
Note These instructions apply to Standard mode and the default Home screen layout.
From a Home screen, navigate: Settings Settings icon > Device care Device care settings icon > Storage.
Tap CLEAN NOW.
Clearing the cache and restarting your phone is all you need to do. It's not actually infected your phone at all its just a clever trick with easy removal most people don't know about.