rdp – Initiates a remote desktop session from server 2019

We have provided a Server 2019 data center and configured it as a terminal server. We can do RDP quite well to Everything seems to be working well with this server. The clients that connect to this server are "Thin Clients" (created with ThinStation).

For older reasons we need temporary access to another server (2012 R2). Therefore, we have provided an RDP icon on the desktop of the 2019 server. Then we noticed that we cannot do RDP out from this 2019 server.

Things we've checked that work:

  • RDP access from any other computer to the 2012R2 (as always)
  • No AV is installed on both servers
  • Windows firewall disabled and tried again
  • DNS resolves well, also tried on IP (same result)

We notice an entry in the event logs of the receiving server (2012R2):

Listener RDP-Tcp has received a connection (event ID 261)

This is usually followed by an event with the ID 1149 "User authentication successful". With this combination, however, this event never follows. After a short time we receive an "internal warning" on the initiating server, no further events are logged at both ends.

I conclude that the server reaches the destination, but the process fails somewhere in the initiation phase (I know event ID 1149 contains a confusing description even before credentials were entered).