Sandbox Plugins Error: System.Servicepoint.EndpointnotFoundException.

Hi All,

We are trying to separate back-end roles from a CRM implementation, current implementation have only two servers 1. Full-server role 2. Database server.

We are trying to have the back-end roles (Async and sandbox) services into another server. and below are the steps we have taken.

1. Installed Back-end server roles into new server (Server 2) and configured the CRM to connect to current instance.

2.  Disabled Async services, sandbox services from the Server 1.

Now CRM behaves are expected, all the system jobs are triggerring well. however when there is any execution of Sandbox plugin, there is an error as below

"System.ServicePoint.EndPointnotFoundException: There was no endpoint listening at net.pipe://localhost/CRMSandboxHost that could accept the message. This often caused by an incorrect address or SOAP action.

I'm sure there is some SPN/configuration missing, but cannot find any viable solution online