There are 3 ways your notifications may be getting blocked on Windows:
1. Ensure that you aren't on focus mode/DND since this will block notifications from showing up.
2. Check within your browser settings and ensure that you haven't blocked notifications.
3. Within your "Settings", the system may have, by default, blocked notifications from Google Chrome or whichever browser you are using. Go to "Notifications and actions" within your "Settings" and switch on the toggle if it's off.