Mac notifications not working after update

To fix Mac notifications after an update, restart your Mac first, then check your Focus sync and per-app alert settings.

Try these quick solutions:

Disable Focus "Share Across Devices"

macOS updates often turn on or reset cross-device sync with your iPhone or iPad, meaning an active Do Not Disturb or Focus mode on your phone might be blocking your Mac.

• Open System Settings > Focus.
• Look for Share Across Devices at the top and toggle it Off.
• If that corrects the issue, then check your other devices for Focus mode status (one user recently had inadvertently set their Apple Watch to Do Not Disturb, for example).

Verify Per-App Alert Styles

An update can reset individual app display preferences to "None".

• Open System Settings > Notifications.
• Click on the specific app that is not working.
• Make sure Allow Notifications is toggled on.
• Set the Alert Style from None to Temporary or Persistent as desired.
• Ensure sound and badge toggles are turned on if you need them. 

Check Global Notification & Sleep Settings

• Go to System Settings > Notifications.
• Check options under Notification Center to ensure notifications are allowed when the display is sleeping or locked, or if Apple Intelligence summary features are hiding or delaying your alerts.

More info from Apple: Notifications settings on Mac - Apple Support

One more note, the current version of macOS is 27.0.1. Based on your post you are running an older version (27.0), so the first step is to update your Mac to the current version.

See: Update macOS on Mac - Apple Support

Since notifications stopped working after upgrading to macOS Golden Gate 27.0 on your MacBook Air, I would  suggest working through the following steps. 

They are based on Apple Support documentation, as the exact cause is not  yet clear.

First, open System Settings >> Focus and temporarily turn off any active Focus mode and of sharing across other devices  

Then go to System Settings >> Notifications, select an affected app, and check that notifications are enabled and the preferred alert style is selected.

If only one app is affected, check its own notification settings, too. 

Restart your Mac and test again.

Next, click the date and time to open Notification Centre. 

If notifications appear there but desktop banners are missing, the issue may be with how alerts are displayed rather than with notification delivery itself.

Apple's instructions are available here: Focus settings and notification settings.

If notifications still aren’t working, try starting your Mac in Safe Mode and test again. 

If they work in Safe Mode but not during normal startup, software or processes loaded during normal startup may be contributing to the problem.

You can also test notifications in a separate macOS user account. 

If they work in the new account but not your usual one, the issue may be related to your original account's settings or environment. 

Neither test identifies the cause conclusively.

If the problem persists, check Apple menu  >> About This Mac to confirm your macOS version, and note whether the issue affects all apps or only certain ones. 

That information will help narrow down the next steps without resorting prematurely to resetting settings or reinstalling macOS.

For me the notification center does not appears and if I open the Settings and click in it, it does not opens the notifications settings. Super weird.

I already tried to kill the process and also update my macOS version. Doesn't work at all.

[Edited by Moderator]