I have recently acquired a popup ad virus on my iMac (macOS High Sierra 10.13.6). This virus sends my multiple popup ads through out the day telling me my Nortons or McAfee has expired, My Mac has a virus sent from a mock apple website page and virus protection ads. Each popup includes costsimpleplay.com on the notification. I have blocked this site from notifications and popups with no success. When I run my Malwarebytes it tells my my computer is clean.
I have found one site about this virus, however it only explains how to rid it on a PC. Please help!