OperationalError: connection refused

OperationalError: connection refused

$ psql -h localhost -p 5432 -U user -d db
psql: error: connection to server at "localhost" (::1), port 5432 failed: Connection refused

Why this happens

The database server isn’t running, wrong host/port, firewall blocks, or credentials are invalid.

Fix

Start the DB service, verify settings HOST, PORT, USER, PASSWORD, and network reachability.

Wrong code

DATABASES = {
  'default': {
    'ENGINE': 'django.db.backends.postgresql',
    'HOST': 'localhost',
    'PORT': 5433,  # wrong
  }
}

Fixed code

DATABASES = {
  'default': {
    'ENGINE': 'django.db.backends.postgresql',
    'HOST': 'localhost',
    'PORT': 5432,
    'USER': 'app',
    'PASSWORD': 'secret',
    'NAME': 'appdb',
  }
}