You try to use the phoenix getting started guide on windows and the task “mix ecto.create” fails with an useless error? Chances are your postgresql database isn’t available with the ecto default credentials “postgres”:“postgres”. Try to logon to the database with the credentials “postgres”:“Postgres1234” and change the password for the user to “postgres”. Also, don’t forget to change the password of the Windows user “postgres”. Update 15.11.2015: You also have to change the logon information for the service, otherwise postgresql won’t start after an restart.