Language Problem on Ubuntu 14.04

Droplet Ubuntu 14.04 LTS Error on installing postgresql:

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_PAPER = "en_US.UTF-8",
        LC_ADDRESS = "en_US.UTF-8",
        LC_MONETARY = "en_US.UTF-8",
        LC_NUMERIC = "en_US.UTF-8",
        LC_TELEPHONE = "en_US.UTF-8",
        LC_IDENTIFICATION = "en_US.UTF-8",
        LC_MEASUREMENT = "en_US.UTF-8",
        LC_TIME = "en_US.UTF-8",
        LC_NAME = "en_US.UTF-8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.

With this error postgresql cant start:

Setting up postgresql-9.3 (9.3.4-1) ...
Error: The locale requested by the environment is invalid.
Error: could not create default cluster. Please create it manually with

  pg_createcluster 9.3 main --start

or a similar command (see 'man pg_createcluster').
update-alternatives: using /usr/share/postgresql/9.3/man/man1/postmaster.1.gz to provide /usr/share/man/man1/postmaster.1.gz (postmaster.1.gz) in auto mode
 * No PostgreSQL clusters exist; see "man pg_createcluster"

I’ve tried various methods presented by google, none solved my problem:

apt-get install --reinstall locales && sudo dpkg-reconfigure locales

dpkg-reconfigure locales

locale-gen en_US.UTF-8

locale-gen --no-purge --lang en_US.UTF-8