Hi, I was near to the end of deploy but something was wrong.
I thinking that I was already done all configuration on a server and on a project. The last command which I do is: mix edeliver build release --branch=configure_deploy_branch
And when I do so I get the next output:

BUILDING RELEASE OF MY_APP APP ON BUILD HOST

-----> Authorizing hosts
-----> Ensuring hosts are ready to accept git pushes
bash is installed and the default shell
fatal: not in a git directory

A remote command failed on:

  ubuntu@stage.my_app.net

Output of the command is shown above and the command executed
on that host is printed below for debugging purposes:

FAILED with exit status 128:

    current_shell="$0" || :
    [ -z "$current_shell" ] && current_shell="$SHELL"
    case "$current_shell" in
      (*bash*) echo 'bash is installed and the default shell'  ;;
      (*zsh*)  echo  'zsh is installed and the default shell'  ;;
      (*)
       echo
       echo "You are using an unsupported shell: '$current_shell'"
       echo "edeliver requires either bash or zsh to be installed"
       echo "and the default shell for the build user 'ubuntu'"
       echo "on your build host: 'stage.my_app.net'."
       exit 1
       ;;
    esac
    set -e
    if [ ! -d /home/ubuntu/deploy/my_app/app_builds ]
    then
      mkdir -p /home/ubuntu/deploy/my_app/app_builds
      cd /home/ubuntu/deploy/my_app/app_builds
      git init
      git config receive.denyCurrentBranch ignore
    else
      cd /home/ubuntu/deploy/my_app/app_builds
      git config receive.denyCurrentBranch ignore
    fi

Here you can find my configuration .deliver/config :

APP="my_app"

BUILD_HOST="stage.my_app.net"
BUILD_USER="ubuntu"
BUILD_AT="/home/ubuntu/deploy/my_app/app_builds"

STAGING_HOSTS="stage.my_app.net"
STAGING_USER="ubuntu" 
DELIVER_TO="/home/ubuntu/deploy/my_app/app_releases"

AUTO_VERSION=git-branch+git-revision+build-date+build-time

# for implementing prod.secret.exs in prod server

pre_erlang_get_and_update_deps() {
  local _prod_secret_path="/home/ubuntu/deploy/my_app/app_config/prod.secret.exs"
  if [ "$TARGET_MIX_ENV" = "prod" ]; then
    __sync_remote "
      ln -sfn '$_prod_secret_path' '$BUILD_AT/config/prod.secret.exs'
    "
  fi
}

# for compiling assets
.......

Ask if you need some additional information.

I saw something similar here , but my ~/.ssh/config already changed and still nothing