If you are unable to connect to your DHCP server through RSAT, first check the security event log on the DHCP server. You should see an “Audit Failure” event, like what is shown below. If you do, its probably because your credentials are not being passed correctly.
To verify this, open a administrator command prompt on the computer that you are using RSAT on.
Run “klist”, if it looks like what is below your credentials are not cached.
In order to fix this, RDP from any computer on your network into the workstation that you are using RSAT on as your -OU or -PR account. Then logout.
Now go back to the computer with RSAT and rerun “klist” from the administrator prompt, and you should see an output like what is below.
If you do you should now be able to connect to your DHCP server with RSAT. If you still can not connect please open a ticket with the service desk.