I have spent weeks dealing with this issue. I have parked the iOS notification requirement of my app and moved on to other non-notification related areas. But now, I need to solve this problem. I have not experienced this problem with Azure and Android (works 100% of the time).
After starting with the following Microsoft example ...
Send and receive push notifications with Azure Notification Hubs and Xamarin.Forms (posted 11/27/2019)
...and following the provided instructions exactly, I was initially able to use the Dispatcher project to send Azure Push Notifications to both iOS and Android.
After a week development the iOS project just stopped working for no apparent reason. I enhanced the NotificationHubSample command-line Dispatcher to allow the listing and deleting of Azure notification hub registrations.
Occasionally, the iOS (actual iPhone) would begin receiving notifications. However, most of the time, the iPhone would not receive notifications and, quite a few times, would not even register with Azure. The Azure portal mirrored these observations.
I have not had any problems at all with Android Firebase notifications being routed through Azure Notification Hub **
Some times I am able to coerce the iOS Xamarin NotificationHubSample project to register with iOS by...
1) Manually delete all Azure Notification Hub registrations using my modified Dispatcher app.
2) Remove the app from both the physical iPhone and the Android emulated devices.
3) Stop Visual Studio 2019
4) !!! Turn off the iPhone, Mac and PC and wait for at least 20 minutes (some times over night) !!!
5) Turn on the iPhone, Mac, and PC.
6) Start Visual Studio 2019 and load the baseline project mentioned above.
7) Execute with iOS, Android, and Dispatcher projects in DEBUG mode.
...however I think maybe Azure/Xamarin/iOS decides to work on its own and these steps are being performed in vain. I have had days in which the iOS Xamarin NotificatrionHubSample project would not register with Azure notification hubs.
My configuration ...
MacBook Air macOS Catalina 10.15.4
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Visual C++ 2019 00435-20052-85367-AA449
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