Any operation on a VPS gives "Cannot lock VE" warning
A VPS is locked when some operation (backup, migration, start / stop, etc.) with that VPS is in progress. You can determine which process is holding VPS #VEID using the following command on the hardware node:
You can kill that process if needed, but make sure that the process is really killed. If there is no process with that PID on the node, just remove the lockfile.