Welcome to the forum @ben80
v2.0.1.27-2.0.1.27_canary_2016-10-14
Added support for “caffeinate” on OSX to prevent sleep during backups
Are you on battery? That might explain it. Does ps show a caffeinate process like above from Duplicati?
Caffeinate prevents my laptop from sleeping is some evidence that it worked, unless it broke somehow.