PIVOTING, TUNNELING, AND PORT FORWARDING - HTB Academy

I have been trying to complete the 2nd question in the first module:

Apply the concepts taught in this section to pivot to the internal network and use RDP (credentials: victor:pass@123) to take control of the Windows target on 172.16.5.19. Submit the contents of Flag.txt located on the Desktop.

I have checked the etc/proxychains.conf for the correct socks4 127.0.0.1 9050. I have run proxychains nmap -v -sn 172.16.5.1-200 and every time it responds with no results. I have tried pwnbox’s, my own baremetal with multiple different vpns. Am I missing something? Has anyone experienced the same issue here?

EDIT:
I am unsure as to why, maybe due to firewalls on the windows machine, but I managed to bypass and pivot using an explicit and direct tunnel: ssh -L 3389:172.16.5.19:3389 ubuntu@10.129.x.x -N. Once that was configured, I was able to run xfreerdp /v:localhost:3389 /u:victor /p:pass@123 which gave me access via RDP to get the flag.txt