Farm Remote App 2012 R : Your system administrator does not allow the use of default credentials to log on to Work Resources

Hi

Here is the situation:

I have a Farm with 3 servers W2012R2 in a Domain

Server1                           Server 2                                   Server3

RDSession Host            RDSession Host                             RDSession Host
Connection Broker        Connection Broker (Passive)
RD Web Access

2 DNS Alias : - poc.mydomain.local (Use for the RD Web Access and points to Server1
                    -poccb.mydomain.local (Use for the Connection Broker and points to Server1)

I have setup the Connection broker in HA with Server2 as Passive Server : DNS Round Robin poccb.mydomain.local (Server1)

The certificate Manager has generated 2 CA certificates :
- 1 for the RD Web Acc (poc.mydomain.local
-1 for Connection Broker SSO and for publishing

I have created 1 Group Policy for these 3 servers and 1 GP for my client Windows 7 SP1.

Server GPO :
Computer/Administrative Templates/Windows Components/Remote Desktop Services/Remote Desktop Session Host/Security
Always prompt for password upon connection=Disabled
Require use of specific security layer for remote (RDP) connections : SSL (TLS 1.0)
Set client connection encryption level : High Level

Client GPO
Computer/Administrative Templates/System/Credentials Delegation = Allow delegating default credentials (Concatenate OS defaults with input above)
TERMSRV/POCCB.mydomain.local