You're trying to log in to the server with your user account, but you're presented with a screen like this and can't log out or switch users.

1) Click on the monitor icon at the top and middle

2) Select Console

3) This will bring you back to the Windows Login screen.

4) Push the portion in the top midle that says "Send Ctrl-Alt-Del". This will prompt you to enter your login details

If you do not see this portion, click on the thunderbolt icon at the top and select "Send Ctrl-Alt-Del"