Service Bus Queue is not available now !

The Service Bus Queue which had been running without any error, occurs the following error.

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An unhandled exception of type 'System.UnauthorizedAccessException' occurred in Microsoft.ServiceBus.dll

Additional information: The remote server returned an error: (401) does not allow claim is empty TrackingId:. F1ae8661-2b46-433e-9621-c7b91c5927e3_G7, SystemTracker: digipub.servicebus.windows.net: DigipubOrder_Session, Timestamp: 7/20/2016 2:18:55 AM
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By debugging, I found that the error ocurrs at "namespaceManager.QueueExists (queueName)" in the following C# source.  I checked again this "ConnectionString" by the Azure management portal.  It was the same string.

- Is there an expiration date of ConnectionString?

- In that case, how can we update it?

- Or is there any possibility of adverse effect of the current Service Bus Queue version-up? In that case, please tell us how can we solute the problem.

- In such a case as  "destructive" version-up giving a direct impact on the running program,  where will the pre-announcement be done?

Any help and hint is most welcome.
Thank you in advance.
 

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(C# source for PowerShell library)

        public QueueClient InitializeParamWithSession(string connectionString, string queueName, bool useSession, bool? deleteAfterReceipt)
         {
             QueueDescription queueDescription = new QueueDescription(queueName)
             {
                 RequiresSession = useSession
             };

            var namespaceManager = NamespaceManager.CreateFromConnectionString(connectionString);

            if (!namespaceManager.QueueExists(queueName))
             {
                 namespaceManager.CreateQueue(queueDescription);
             }
             var GQueueClient = CreateQueueClient(connectionString, queueName, deleteAfterReceipt);
             return GQueueClient;
         }

        public QueueClient CreateQueueClient(string connectionString,string queueName, bool? deleteAfterReceipt)
         {
             ReceiveMode receiveMode;
             if (deleteAfterReceipt != null)
             {
                 if (deleteAfterReceipt == true)
                 {
                     receiveMode = ReceiveMode.ReceiveAndDelete;
                 }
                 else
                 {
                     receiveMode = ReceiveMode.PeekLock;
                 }
                 return MessagingFactory.CreateFromConnectionString(connectionString).CreateQueueClient(queueName, receiveMode);

            }
             else
             {
                 return MessagingFactory.CreateFromConnectionString(connectionString).CreateQueueClient(queueName);

            }
         }
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