Failed RPC connection to the node ejabberd@personal: nodedown

OS: ubuntu 16.04
ejabberd: 16.01
I try backup with command: sudo -u ejabberd ejabberdctl backup /tmp/ejabberd.backup --no-timeout and got error:
Failed RPC connection to the node ejabberd@personal: nodedown.

$ sudo ejabberdctl status
Failed RPC connection to the node ejabberd@personal: nodedown

But my server work on this node, and my client can connect to it:
$ sudo -u ejabberd ejabberdctl start
ERROR: The ejabberd node 'ejabberd@personal' is already running.

Any ideas? Forexample I need to instal some package or add some to settings?