If you aren't receiving notifications on WhatsApp for web, make sure your browser is properly configured:
Click Turn on desktop notifications in the blue banner at the top of the chat list.
Follow the instructions on the screen and click Allow.
If you don't see the blue banner, refresh the page. If you still don't see the banner, you may have muted or turned off notifications from WhatsApp settings. Learn how to configure your notification settings in this article.
https://web.whatsapp.comis set to Block, highlight it and click the X.
You can learn more about Opera notifications on the Opera Help website.