Since having the latest "security update" on my S9 I've been getting advertising whenever I plug it in and often at random and I can't exit out of it. I haven't downloaded any new apps and haven't changed anything but this is getting annoying.
Have you first tested your device in safe mode to see if a third-party downloaded application is causing your symptoms?
To put the device in safe mode, first power down the device.
- Hold down the power button until the "SAMSUNG" logo appears
- Immediately release the power button then hold the volume down key until you boot into safe mode
As what @SamsungZell said, This is due to a 3rd party app you downloaded