I've created a Virtualbox Windows 10 VM and a VMWare Windows 10 VM, but in both situations when I try and configure sonarr, radarr, and sabnzbd into the nzb360 app, I'm unable to connect to the APIs. The APIs can't be reached. If I run the 3 apps in my host machine then everything works perfectly. I tried disabling host and guest firewall, but it's still failing to make this connection. I also used canyouseeme.org and was able to see all 3 ports as open so issue is only happening inside a VM. Any help is appreciated.

when you put your phone in 3g/4g, can you access it then ? You should, if canyouseeme detects the services as well. And it could mean the local connection to your VM is not properly set up. Maybe they're on different subnets, or client-to-client connections are not allowed or something.