I had the same problem and tired all the above solutions and did not work for me! the problem was because multiple networks make conflict between VMware and VirtualBox, and other VPN connections. The solution i followed is:
uninstall virtualbox and reinstall the last update of it
If solution 1 not working, try this uninstalling all VPN programs, VirtualBox, Genymotion and reinstalled VirtualBox and Genymotion again. both solutions worked with me