Hi, I'm John! I will help you with this.
These types of pop-ups try to scare you into calling a fake "Microsoft" number, but Microsoft never asks users to call for support this way.
Since the message keeps coming back, it's likely stored in your browser’s cache or a bad extension was added. Here’s what I recommend to clear it out:
Close your browser completely (use Task Manager if needed: press Ctrl + Shift + Esc, find your browser, right-click, and select End task).
Clear your browser cache and cookies in Microsoft Edge:
> Open Microsoft Edge and press Alt + F keys to bring menu, then click on "Settings".
> Click "Privacy, search, and services"
> Under "Clear browsing data" > in "Clear browsing data now" > click "Choose what to clear"
> Check Browsing History, Cookies and other site data, and Cache image and files.
> Click "Clear now".
> After that, click "Cookies and site permissions" from the left sidebar.
> Click on "Manage and delete cookies and site data".
> Make sure that the option to "Allow sites to save and read cookie data" is turned on.
Check for unwanted extensions and Reset your browser settings in Microsoft Edge:
> Open Edge again, press Alt + F keys, and go to "Extensions." Remove all extensions, then test again to see if it's working.
> If the issue still persists, go to Edge settings again by pressing Alt + F keys > Settings > and click on "Privacy, search, and services." > Under "Clear browsing data," click on "Choose what to clear" and select all options except saved passwords. > Click on "Clear now." > Test the browser once more to see if the problem is resolved.
Scan your PC again: Since you've already run Microsoft Defender and Malwarebytes, you might also try Microsoft’s Malicious Software Removal Tool (MSRT) by searching for it in Windows Security: https://www.microsoft.com/en-us/download/detail... Download and run.
Once you've done that, restart your PC and see if the pop-up is gone.
Click "Reply" below to let me know.
Regards,
John J.D.