Avoid ubuntu auto-suspend

Through the ubuntu UI, go to:

 System -> Power -> Power Saving -> Blank Screen -> Never

Using the command line:

$ sudo systemctl mask sleep.target suspend.target hibernate.target hybrid-sleep.target

After that, reboot the system for changes to take effect.

To make sure they’re disabled, run:

$ sudo systemctl status sleep.target suspend.target hibernate.target hybrid-sleep.target

Every state should read as inactive.

To reactivate sleep you can run:

$ sudo systemctl unmask sleep.target suspend.target hibernate.target hybrid-sleep.target