First try to unlock the pct (assuming your troubled container is 101):
pct unlock 101
if it works just stop and start again the vm. if it does’nt work (my case) try to stop with this
lxc-stop --name 101
if it’s does’nt work (my case) you can force stop with kill command
ps ax | grep lxc
then kill the process with your id (101 for me) kill pid (replace pid by the process name). After that you can just launch again you’r vm
sumber: https://tweenpath.net/force-stop-proxmox-lxc/