conn = _connect(dsn, connection_factory=connection_factory, **kwasync) psycopg2.OperationalError: could not connect to server: Connection refused Is the server running on host "127.0.0.1" and accepting TCP/IP connections on port 5432?

# It happend because you are not running 
service postgresql status # to check the status of database
# if it's Active: inactive the you are getting this error.
# to over ride this error you should up and run server
service postgresql start