If you are seeing pop-up warnings or adverts from Chrome, a website may have permission to send you notifications. You can check and remove this permission in Chrome's settings.
- Open Chrome.
- Click the three dots in the top right corner, then click Settings.
- Click Privacy and security, then Site Settings, then Notifications.
- Look at the list under Allowed to send notifications.
- For any website you don't recognise, click the three dots next to it and choose Block or Remove.
Once removed, that website can no longer send you notifications. For more detail, see Google's guide: https://support.google.com/chrome/answer/3220216