chrome notification extension code example
Example: chrome extension notification not showing
If you are using Mac and Chrome 59+, it might be because the MacOS native notification is disabled for Chrome. Here's two possible solutions:
Solution 1
Open Chrome > Go chrome://flags > Search Enable native notifications > Change it to Disabled > Relaunch Chrome
Solution 2
Go to MacOS System Preferences > Notifications > Turn on Notifications for Banners/Alerts as shown here (likely previously it's Off)