Using standard UBUNTU 16 LTS env. and used enterprisedb.com/downloads PostgreSQL Setup Wizard to install, an "official suggestion" here... So supposing it is plug-and-play.
But the basic (for a "plug and play") not runs (!), psql -h localhost -U postgres
psql: FATAL: password authentication failed for user "postgres" FATAL: password authentication failed for user "postgres"
The user postgres exist, and even after sudo passwd postgres to "postgres", the same error.