Do you still get the popup when not doing anything?
Try clear Your browser history
In all major Internet browsers (e.g., Chrome, Edge, Firefox, IE, Opera), pressing Ctrl + Shift + Delete opens the Clear browsing data window to quickly clear private data and history
Does it still happen?
- If so try starting your browser with apps disabled.
Does it still happen?
If not, one of your browser add-ons would appear to be connecting to this site.
Now it is a bit of a pain, disabling one app at a time to find it.
Start with any app recently added and or apps recently updated.