Unable to access RDS server with NLA enabled

Hello,

I'm trying to install dell Wyse 3040 clients, we'd like to open an RDP session, but while connecting, I have the following message :

    RDP:Connect to myrds.mylan
    RDP: NLA CredSSP Authentication ... 
    RDP: pdu_ssl_send: 5905
    RDP: NLA CredSSP Authentication failed, please check credentials and connection settings.
    ERROR: Connection Failed!

While testing on a Wyse C Class it works perfectly.

Please could someone help on this case ?