All out of sudden, user is not in the sudoers files.

[Esteban Siravegna]

Hey there. I ve been using armbian since a couple of years now. Today, out of the blue, I receive a 'user is not in the sudoers file '. I currently I'm using ARMBIAN Ubuntu 14.04.5 LTS 4.8.4-sunxi. Obivuously, my user WAS a sudoer, actually, it is the only user.

 

Any ideas would be very much appreciated.

 

Thanks!