Hi Pablo , make sure your ctf machine vm and kali vm are on same network , you can check that on your VMWare or VirtualBox network adapter settings , put them both on NAT or Bridged.

Hope this helps , if not then do tell

Hacker | Bug Hunter | Python Coder | Gamer | Reverse Engineering Lover

Hacker | Bug Hunter | Python Coder | Gamer | Reverse Engineering Lover