ACS Configuration using pluginRegistration Tool

Hi all,

Im facing to an issue about the ACS configuration. In fact Im trying to register a service endpoint using the plugin registration tool and when I try to configure the ACS I got the following error:

Trying to find out the ACS Version.

WebException encountered while trying to find out ACS Version.

(503) server unavailable

I have already configure the service bus on Azure and I can see the public key on the connection section. Below the screen capture :

Thanks for Help