While copying data through the ssh tunnel, the mouse moved the etc folder to a subfolder. The connection to the web interface and ssh client disappeared. the VMS were working. they were stopped remotely. I got this error when restarting. next, when downloading from a live cd, after making a backup copy of the virtual machines, we saw that there is no folder in the root etc/ it was found and returned to its place. after the reboot, everything worked perfectly. thank you for your attention.