Trying to create certs

[ulm0]

i'm trying to create a cert, with ./letsencrypt-auto certonly --standalone and get the following output:

Creating virtual environment...
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/virtualenv.py", line 2363, in <module>
    main()
  File "/usr/lib/python3/dist-packages/virtualenv.py", line 719, in main
    symlink=options.symlink)
  File "/usr/lib/python3/dist-packages/virtualenv.py", line 988, in create_environment
    download=download,
  File "/usr/lib/python3/dist-packages/virtualenv.py", line 918, in install_wheel
    call_subprocess(cmd, show_stdout=False, extra_env=env, stdin=SCRIPT)
  File "/usr/lib/python3/dist-packages/virtualenv.py", line 812, in call_subprocess
    % (cmd_desc, proc.returncode))
OSError: Command /root/.local/share/letsencrypt/bin/python2.7 - setuptools pkg_resources pip wheel failed with error code 1

I stopped nginx already. what could be causing this?
i'm using ubuntu server 16.04.1

PS: I've created several certs a few weeks ago using the same method.

[bmw]

This is a duplicate of #2883. There are a number of posts there from people who were able to fix the problem. Additionally, there is a letsencrypt package on Ubuntu 16.04 that we are currently recommending over letsencrypt-auto.