create new user

[roger peppe]

I'd quite like to make a new user on my snappy instance (so that I don't
need to use "ssh ubuntu at ..." every time), but I get this response:

ubuntu at localhost:~$ sudo adduser rog
Adding user `rog' ...
Adding new group `rog' (1001) ...
groupadd: cannot lock /etc/group; try again later.
adduser: `/usr/sbin/groupadd -g 1001 rog' returned error code 10. Exiting.
ubuntu at localhost:~$

What am I doing wrong?

  cheers,
    rog.