I don't get connection anymore

[Pinnacchio]

When i change my MAC address i don't get connection anymore. My provider is TIM, in the past I was able to solve it, but now I have had to reformat everything and it doesn't work anymore.
How can I solve?

P.S .: I installed Kali Linux in virtual with Virtual Box

[Pinnacchio]

If it helps, I solved it by changing /etc/NetworkManager/NetworkManager.conf from managed = false to managed = true. Then I created a bash file where I entered the following commands:

#! / bin / bash
sudo service NetworkManager stop
sudo ifconfig eth0 down
sudo macchanger -r eth0
sudo ifconfig eth0 up
sudo service NetworkManager start

Then just type ./filename.bh and everything will work perfectly.