Why Im getting these erros every 6 seconds fromproftpd?
Aug 13 12:41:27 nike-a proftpd[6317]: nike-a.asd.it - Fatal: unable to open incoming connection: Transport endpoint is not connected
Aug 13 12:41:33 nike-a proftpd[6318]: nike-a.asd.it - Fatal: unable to open incoming connection: Transport endpoint is not connected
Aug 13 12:41:39 nike-a proftpd[6322]: nike-a.asd.it - Fatal: unable to open incoming connection: Transport endpoint is not connected
Aug 13 12:41:45 nike-a proftpd[6336]: nike-a.asd.it - Fatal: unable to open incoming connection: Transport endpoint is not connected
Aug 13 12:41:51 nike-a proftpd[6338]: nike-a.asd.it - Fatal: unable to open incoming connection: Transport endpoint is not connected
Aug 13 12:41:57 nike-a proftpd[6339]: nike-a.asd.it - Fatal: unable to open incoming connection: Transport endpoint is not connected
Aug 13 12:42:03 nike-a proftpd[6360]: nike-a.asd.it - Fatal: unable to open incoming connection: Transport endpoint is not connected
Aug 13 12:42:09 nike-a proftpd[6390]: nike-a.asd.it - Fatal: unable to open incoming connection: Transport endpoint is not connected
Aug 13 12:42:15 nike-a proftpd[6417]: nike-a.asd.it - Fatal: unable to open incoming connection: Transport endpoint is not connected
Aug 13 12:42:21 nike-a proftpd[6432]: nike-a.asd.it - Fatal: unable to open incoming connection: Transport endpoint is not connected