Sometimes, I need to lock the elementary os and let some jobs can still work. But I found when I lock the elementary os for a while (> 2h), the network will interrupt. I need the network uninterrupted when the system is locked but I don't know how to do. is there any method?
Please go to the System Settings and select Power. After that please change the option for "Turn of the display when inactive for" to Never. Please be sure to do this for both On Battery and Plugged In.
Also you might want to check the options for closing lid cause if they are set to suspend or something like that, closing lid can cause you problem too.