Mac not receiving iPhone notifications; setting turns off

Based on everything you have described, this does not appear to be a notification settings issue.

The important detail is that Allow notifications from iPhone enables successfully, but the switch turns itself off after approximately 10 to 15 minutes.

At the same time, the list of supported iPhone apps never appears.

Under normal circumstances, macOS should populate that list shortly after the feature is enabled. If the list never appears and the setting subsequently disables itself, the Mac is usually failing to complete its Continuity registration with the iPhone.

Since you have already confirmed that both devices are signed into the same Apple Account, are connected to the same Wi-Fi network, have Bluetooth enabled, and that Handoff, phone calls, and Messages all work correctly, the usual prerequisites for Continuity appear to be satisfied.

I would first confirm that two-factor authentication is enabled for your Apple Account, as it is required for Continuity features.

Next, disable Handoff on both devices, restart both the iPhone and the Mac, then re-enable Handoff on the iPhone first, followed by the Mac. After waiting a few minutes, enable Allow notifications from iPhone again and see whether the application list appears. Apple provides instructions here:

Hand off tasks between Apple devices - Apple Support

If there is no change, sign out of your Apple Account on the Mac only, restart the Mac, then sign back in.

This forces the Mac to register with Apple's Continuity services again and has resolved similar issues for some users. Apple explains how to sign out here:

If no app is set to open a document on Mac - Apple Support

If the problem persists, start the Mac in Safe Mode and test the setting again.

If the toggle remains enabled in Safe Mode, the issue may be caused by third-party software or a login item. Apple describes how to use Safe Mode here:

Start up your Mac in safe mode - Apple Support

Regarding iPhone Mirroring, that is a separate feature. The absence of the iPhone Mirroring application in the European Union does not prevent iPhone notifications from being forwarded to a Mac. Since your friend receives iPhone notifications without iPhone Mirroring, that is consistent with Apple's implementation.

At this point, because the setting disables itself automatically and the list of supported apps never appears, I would be more inclined to suspect a Continuity registration failure or a software issue in macOS 26.5.2 than an incorrect user setting.

Two questions would help narrow it down further.

Is this a personal Mac, or is it managed by a workplace or educational institution?

This type of setup usually involves a Mobile Digital Management derive like Jamf / Intunes or similar 

If you create a new macOS user account and sign into your Apple Account there, does Allow notifications from iPhonestill turn itself off after several minutes?

If the behaviour is identical in a new macOS user account, that would strongly suggest a system-level issue rather than a problem with your current user profile.

Apple also has an overview of the requirements for Continuity features here:

Continuity features and requirements for Apple devices - Apple Support

From the symptoms that you described, the issue does not appear to be with notifications themselves.

The most important clue is that Allow notifications from iPhone turns itself off and the list of iPhone apps never appears.

Under normal circumstances, enabling this setting immediately displays the list of eligible iPhone apps. If the switch automatically disables itself, the Mac is generally failing to complete the registration process required for iPhone notifications. (Apple Support)

If there are any of the following installed, Uninstall them as they maybe a contributing factor

Third Party 2 Way Firewalls, Commercial VPNs , Third Party Security Software , Third Party Disk Cleaners / Optimizer 

First, confirm that both the Mac and iPhone are signed in to the same Apple Account and that both devices are running compatible software versions. Apple also requires Wi-Fi, Bluetooth, iCloud, and two-factor authentication to be enabled for Continuity features, including iPhone notifications on the Mac. More information is available in Apple's Continuity overview: Continuity for Mac and iPhone.

Next, restart both the Mac and the iPhone. After both devices restart, open System Settings > Notifications on the Mac and enable Allow notifications from iPhone again. If the feature is working correctly, the list of supported iPhone apps should appear immediately beneath the switch. Apple documents this behaviour here: Manage iPhone notifications and Live Activities on Mac.

It is also worth checking whether other Continuity features function normally. For example, verify whether Handoff, Universal Clipboard, iPhone Mirroring, or making and receiving iPhone calls on the Mac work correctly. If none of these features work, the problem is likely related to the Continuity connection between the two devices rather than notifications alone. 

If the setting continues to disable itself automatically, signing out of the Apple Account on the Mac, restarting, signing back in, and allowing iCloud to complete synchronization may resolve a corrupted Continuity registration. 

If the problem persists after that, it may indicate a software issue that requires Apple Support to investigate.

There have been reports from other users experiencing the same behaviour, where the notification toggle turns itself off and no applications are displayed, suggesting this may be an issue affecting some systems rather than an isolated configuration problem.

To narrow the cause further, it would be helpful to know the iPhone model, the installed iOS version, whether iPhone Mirroring works between the two devices, and whether the Allow notifications from iPhone switch turns itself off immediately or only after a few seconds. Those details should indicate whether this is a Continuity configuration problem or a software defect.

The latest version of macOS is 26.5.2. Learn how to update the software on your Mac and how to allow important background updates.

The latest version of iOS and iPadOS is 26.5.2. Learn how to update the software on your iPhone or iPad.

Thank you for providing all of those details. The key symptom is that when you enable Allow notifications from iPhone, the setting turns itself off again and the list of iPhone apps never appears. That is not the expected behaviour. If everything is working correctly, enabling the setting should quickly display the apps that can send notifications to your Mac.

Since you have already confirmed that both devices use the same Apple Account, are connected to the same Wi-Fi network, have Bluetooth enabled, iCloud syncing is working, Handoff, calls and iMessage continuity are functioning, and both devices are running the latest software, this does not appear to be a basic connectivity issue.

Because you are in the European Union, it is worth confirming that your Apple Account country and region settings are correct, even though iPhone Mirroring is unavailable there.

Apple explains how to check or change these settings here: Change your Apple Account country or region.

It is also worth toggling Handoff off and back on, even if it is already working, as this can sometimes refresh Continuity services. Apple provides the steps here: Use Handoff on your Mac, iPhone, iPad, and Apple Watch.

The fact that the setting switches itself off automatically is the most concerning part. Combined with the missing app list, it suggests that macOS is not completing the notification forwarding registration with your iPhone. This can be caused by a Continuity registration problem, an Apple Account issue, or a software bug.

One question that may help narrow this down is whether the setting turns off immediately, after a few seconds, or only after you close System Settings. I would also be interested to know whether notification forwarding has ever worked on this Mac or if this has been the behaviour since it was first set up.