Can't connect to VM via RDP

Question

I have an ubuntu 18.x server. I installed virtualbox on the server and configured a new VM using these instructions. When I try the last step I get an error window

I also noticed that when I run netstat, the IP associated with my VM's port is 0.0.0.0

But when I run nmap on my servers IP I get this

PORT     STATE SERVICE
22/tcp   open  ssh
139/tcp  open  netbios-ssn
445/tcp  open  microsoft-ds
5001/tcp open  commplex-link

Where the last row is the port number of my VM

How can I fix this to connect to my VM via RDP?