Wyse T50 network/RDP settings issue - won't authenticate

Recently purchased the Wyse T50(Tx0) and have tried to replicate the settings from our current Wyse S10 models but it won't authenticate me when logging in.

I have filled in the Wired Network Connection section (IPv4) with details: Address, Netmask, Gateway, DNS Servers, Search domains. It states Connection Established at the top of the screen.

Also, I've added broker server and logon domains details to the RDP.

But it will not let me log in as a network user stating authentication failure. We use windows Server 2003 and have several client servers. Any help? Thanks!