Enable \ Disable Web Push Notification in FireFox

1. Click the padlock icon in the address bar.
   
2. Click the arrow in the Site Information drop-down panel.
3. Click More information in the next panel to bring up the Page Info window. 
4. Click the Permissions tab.
5. Under Send Notifications, choose a notification option: Always Ask, Allow, or Block. If your choices are grayed out, deselect the Use Default checkbox. 

Alternatively, you can:

1. Click the menu button and select Options.
   

        
   
   

2.  Click Privacy& Security from the left pane. 
3.  Scroll to the Permissions section. 
4.  Click the Settings button to the right of Notifications. 
5.  Select Allow or Block from the Status drop-down for any of the websites. 
6.  Click the Save Changes button.