Snapshot Backup Stopped


I'm trying to run a Snapshot restore and it got through to the last item before "Snapshot Finishing" and is stuck on "Files : plugins" at 25% (1/4), although there are more than 4 plugins installed on the site.

There is an error that reads, "Unable to create directory /var/www/vhosts/ Make sure the parent folder is writeable."

I haven't aborted the restore yet. How can we get this backup fully restored successfully at this point?