sharepoint online – Can not debug our remote event sink using the Azure service bus. "One or more services have not been registered with Microsoft Azure Service Bus."

I am developing a remote event sink for our site collection. so inside Visual Studio 2015, I did the following: –

  1. I've created a new SharePoint add-in hosted provider application. I've added the code according to this link https://blogs.msdn.microsoft.com/kaevans/2014/02/26/attaching-remote-event-receivers-to-lists-in-the-host-web /.

For the debug site collection, I chose a collection of online enterprise wiki test sites, on which I enabled the application side-loading feature.

  1. In Azure, I created a new service bus, as follows >>. I've copied the main connection string: –
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  2. inside the visual studio project >> Properties >> SharePoint >>, I've added the main connection string of the above service bus, as follows: –
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  3. I run the project >> where I received this message >> I select the list >> click on "Trust": –
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  4. I have the homepage of the application as follows: –
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  5. the application is correctly added in the content of my site: –
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but the visual studio stops working and displays these 2 messages: –
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One or more services have been unsubscribed from Microsoft Azure
Bus service. Can not Register Services / AppEventReceiver.svc on
Microsoft Azure Service Bus: Unable to Connect to Remote Server

so I'm not sure what's going on? why is the service bus not working and, therefore, we are not able to debug our remote event sink?

here is my AppManifest.xml: –




  
    CustomerServiceKB
    ~ remoteAppUrl /? {} StandardTokens
    ~ remoteAppUrl / Services / AppEventReceiver.svc
    ~ remoteAppUrl / Services / AppEventReceiver.svc