I have struggled a bit trying to understand while my Ubuntu 16.04 wasn’t waking up with the common  etherwake  commad.

I found the solution on this link:

you should disable Default option in Network-Manager GUI and enable only the Magic option. If you try this, then you should check if everything is ok opening the shell and issuing this command:

Shell

sudo ethtool *<your_eth_device_here>*

1 2	sudo ethtool *<your_eth_device_here>*

You should see the line:

Shell

Wake-on: g

1 2	Wake-on: g

If it’s not g but d or something else, something could be wrong.

Once done that, and verified with the command  ethtool <myNetinterface> | grep "Wake-on:" , all started to work again 🙂