Good day @sbstn,
Have you checked the autopilot's getting started correctly? You can check that by looking for the process' PID (with top for example) and checking it keeps it (if the autopilot can't get started it'll keep trying, starting new processes). If the PID is changing that means the autopilot can't get started and it might be some hardware problem.
If that's not it, the problem might be windows' firewall getting in the way, try disabling it to check if you can connect without it. This is the most probable cause and it's quite common when working with windows machines.
Also, how are you connecting the brain and PC? Did you connect an ethernet cable to the brain? Through it's wifi?