Hi Patrick,
Could you please try below suggestions?
1. Disable firewall and anti-virus. (Note: It's recommended to configure access rules to allow your app through the firewall or real-time antivirus protection instead of disabling them entirely.) - Restart Mendix Studio Pro and run the app again.
2. Verify that ports 8080 and 8083 are not being used by any other application.
3. Try changing your network, perhaps by using a hotspot?
Document for your reference:
https://docs.mendix.com/refguide/mobile/getting-started-with-mobile/prerequisites/#31-make-it-native-app
were you able to solve it?