I initially ran ~# curl -s | sudo bash, which itself installs and uses git. Since that failed, I then tried to install two older versions using git directly, which also failed. The curl command only reads the shell script file from the mailinabox site which is then piped to bash and run with sudo to ensure elevated privileges. That is no different than downloading the file to a fresh Ubuntu 14.04.5 x64 DigitalOcean VPS and running it from there as the root user.

The only way I found to successfully install Mail-in-a-Box is to eliminate the email address validation during installation. I did that by performing these steps:

  1. Create a new Ubuntu 14.04.5 x64 DigitalOcean VPS.
  2. Login as root using ssh.
  3. Install git by entering: apt-get install git
  4. Download the latest release of Mail-in-a-Box to the VPS by entering: git clone
  5. Edit the questions shell script at ~/mailinabox/setup/ to delete validate-email from line 54, by following either of these steps:
    A. Use FTP to download the file to your workstation, edit it using a text editor, and upload the edited file to the VPS overwriting the original.
    B. Run a text editor directly on the VPS and edit the file in place.
  6. Change to the mailinabox directory by entering: cd mailinabox
  7. Run the script by entering: setup/
  8. Allow the installation to run, and complete the setup process by answering the questions presented. When entering the requested email address, be certain that the address entered is correct, and is entered in all lower-case characters.

It should be noted that this only serves to work around the initial installation problem. Email addresses still will be validated during normal use of Mail-in-a-Box.

I hope that others find this helpful.