Microsoft.Azure.NotificationHubs.Messaging.MessagingException: Unexpected exception encountered

Question

I have put our notification implementation into production and it has been working fine, however I am randomly getting MessagingException errors, and in the last 10 minutes I am continually getting this exception.
As you can see it originates from calling CreateOrUpdateInstallationAsync.
Any ideas what the issue is?

I have only used 15k of my 200k registered devices.

Regards

Chris

Full Exception information: Microsoft.Azure.NotificationHubs.Messaging.MessagingException: Unexpected exception encountered TrackingId:a283cf9b-418c-419d-a937-af654ed9a816,TimeStamp:2020-10-01T07:05:24.3415699Z
---> System.OperationCanceledException: The operation was canceled.
at System.Threading.CancellationToken.ThrowOperationCanceledException()
at System.Threading.CancellationToken.ThrowIfCancellationRequested()
at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException(SocketError error, CancellationToken cancellationToken)
at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.GetResult(Int16 token)
at System.Net.FixedSizeReader.ReadPacketAsync(Stream transport, AsyncProtocolRequest request)
at System.Net.Security.SslStream.ThrowIfExceptional()
at System.Net.Security.SslStream.InternalEndProcessAuthentication(LazyAsyncResult lazyResult)
at System.Net.Security.SslStream.EndProcessAuthentication(IAsyncResult result)
at System.Net.Security.SslStream.EndAuthenticateAsClient(IAsyncResult asyncResult)
at System.Net.Security.SslStream.<>c.<AuthenticateAsClientAsync>b__65_1(IAsyncResult iar)
at System.Threading.Tasks.TaskFactory1.FromAsyncCoreLogic(IAsyncResult iar, Func2 endFunction, Action1 endAction, Task1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location where exception was thrown ---
at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.DiagnosticsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
at Microsoft.Azure.NotificationHubs.NotificationHubClient.SendRequestAsync(HttpRequestMessage request, String trackingId, HttpStatusCode[] successfulResponseStatuses, CancellationToken cancellationToken)
--- End of inner exception stack trace ---
at Microsoft.Azure.NotificationHubs.ExceptionsUtility.HandleUnexpectedException(Exception ex, String trackingId)
at Microsoft.Azure.NotificationHubs.ExceptionsUtility.TranslateToMessagingException(Exception ex, Int32 timeoutInMilliseconds, String trackingId)
at Microsoft.Azure.NotificationHubs.NotificationHubClient.SendRequestAsync(HttpRequestMessage request, String trackingId, HttpStatusCode[] successfulResponseStatuses, CancellationToken cancellationToken)
at Microsoft.Azure.NotificationHubs.NotificationHubClient.SendRequestAsync(HttpRequestMessage request, String trackingId, HttpStatusCode successfulResponseStatus, CancellationToken cancellationToken)
at Microsoft.Azure.NotificationHubs.NotificationHubClient.CreateOrUpdateInstallationAsync(Installation installation, CancellationToken cancellationToken)