I just tried something that seems to have worked for me.
I use Firefox and thought that maybe something in its settings are conflicting with the AV NIRVANA push notifications setting. So I hovered my mouse over the Firefox shield and saw that it was blocking the items shown below.
So I clicked on the shield and turned OFF the Enhanced Tracking Protection.
I opened another AV NIRVANA window and was prompted again for push notifications, so that alone did not work.
I left the Firefox tracking protection OFF and went to the AV NIRVANA user ID Preferences setting and Enabled Push.
Firefox then prompted me to allow this website to send push notifications and I selected Allow, then AV NIRVANA thanked me for allowing the notifications.
I went back to the AV NIRVANA user ID Preferences setting and Disabled Push and then turned ON the Firefox Enhanced Tracking Protection.
I haven't been prompted to enable push notifications since making those changes.