Genymotion Desktop 3.1 is not fully compatible with VirtualBox 6.1 yet. If you are using this version, please downgrade to VirtualBox 6.0.4.
You can find it at https://www.virtualbox.org/wiki/Download_Old_Builds_6_0.
This issue may be due to security restrictions in macOS which blocks VirtualBox modules installation:
- uninstall VirtualBox (use the VirtualBox_uninstall.tool of the VirtualBox downloaded dmg from https://www.virtualbox.org/wiki/Downloads).
- install it again executing VirtualBox.pkg. At the end of the install, go to System Preferences > Security and Privacy, and then click the Allow button.
For more information, please refer to this article here.
If you are using a VPN, please refer to Genymotion Desktop and VPN