I have a computer that uses RDP to connect to an office Terminal
Server in theroy.  Our office has three computers to DCs and a Server
for off site application access that are running Terminal Services.

On a computer that I am trying to configure.  It will connect to both
DC terminal servers, but will not connect to the 3rd terminal server
for application access.  The IP address is correct and I have repaired
and rebooted several times.

Every other computer can connect to the Application Terminal Server,
and the problem computer can connect to the DC Terminal Servers.

THE QUESTIONS:
1. What would cause 1 client and 1 Terminal Server to not be able to
negotiate a connection.
2. How do I fix the problem.

Check and see who has Remote Desktop rights on the 3rd server.  If you
are not using group policies, you will have to edit the local security
policy on the 3rd server to identify users who are authorized to
utilize TS.

Hope this helps.

I am the Enterprise Admin on the Domain Controller.  I can not even
CONNECT to log in.  It is as if the client gdoes not SEE the TS even
though all the other clients do.

what OS is the client PC?
Also, check your Application event logs on both the TS and the client.
Make sure there isn't a max license issue.
If the client PC is not NT, 2000, or XP PRO, and you're not running TS
Licensing on the host, your license *might* have expired on that
client.

Make sure that port 3389/mstsc isn't blocked on the client by a
firewall program like ZoneAlarm.

You can get a new, 90day temporary license on the client by deleting
(ONLY ON THE CLIENT) HKLM\Software\Microsoft\MSLicensing (back up the
key (Export registry file), first, just to be safe). I don't recommend
doing this unless you've exhausted *all* other possibilities.

How many simultaneous log-ons does it accept at the same time? Is this
going over the limit? What OS does it have? Are you logging on with
domain admin account?

On the other hand instead of using Terminal Services Client on the
workstation use MSRDC (Microsoft Remote Desktop Connection) available
from microsoft.

In your question, you ask "What would cause 1 client and 1 Terminal
Server to not be able to negotiate a connection."

Does this indicate that only 1 workstation is unable to connect to the
non-DC terminal server?

On Terminal servers in administration mode, there is a 2 connection
limit.  But you recieve an error message after you submit a username &
password.  On a terminal server in application mode, you are only
restricted by the number of licenses purchased (& configured).

I would suggest that you eliminate routing issues by creating a telnet
session to the server on port 3389.  You can do this from a command
prompt by typing

c:\>telnet <server ip address> 3389

If everything is configured properly, you should just get a blank
screen.  However, if port 3389 is blocked, you should receive an
error.

Hope this helps.