The server with the mail spool spontaneously rebooted around 19:05 PM.  Because NFS re-binding after a crash is less than reliable, some shell servers may not have properly remounted their file systems.  It may take me several hours to check these.  If you run into a server that hangs when you login, hit ‘df’, or try to retrieve e-mail please generate a support ticket: https://www.eskimo.com/support/osTicket/