To prevent a laptop running debian from sleeping when you close the lid:

Find the logind.conf file and uncomment the handle lid switch and change it from suspend to ignore

1. nano /etc/systemd/logind.conf
2. Find the #HandleLidSwitch=suspend
   1. Change it to HandleLidSwitch=ignore
   2. Save and Exit
3. Restart systemd logind
   1. systemctl restart systemd-logind
4. Check its status
   1. systemctl status systemd-logind

Reference Link

I am running proxmox on a thinkpad laptop. How can I close the lid but keep proxmox running?