CRM SDK 2015 - Plugin Registration Tool - CRM Organizations List is Blank After Login

Hello,
I am working with Microsoft Dynamics CRM 2016 Online Update 1.

I have downloaded Microsoft Dynamics CRM SDK for 2013, 2015 and 2016.

After I Login using Plugin Registration Tool from SDK versions 2013 and 2015, it seems that it find my Organization and shows me the list of CRM Organizations, but when I choose any Sandbox Instance it shows the same Choose CRM Organization Form again but with the blank list this time.

So, I am unable to connect my Microsoft Dynamics CRM Sandbox Instance (but I am able to connect CRM Production Instance using Plugin Registration Tools from SDK versions 2013 and 2015).

I am able to connect all CRM Instance using Plugin Registration Tool From SDK version 2016.

I am using ACS Authentication for configuration of Azure Service Bus End-Point and Plugin Registration Tool from SDK version 2016 require SAS Authentication, so need to access CRM Sandbox Instance from Plugin Registration Tool of SDK version 2015. 

Plugin Registration Tools I Used are:

1. Product Version: 6.1.1.1143 (SDK 2013)

2. Product Version: 7.1.1.6680 (SDK 2015)

3. Product Version: 8.1.0.7629 (SDK 2016)

Has anyone had his issue and resolved it ?

Any Solution?

Thanks.