After making changes to the pg_hba.conf or postgresql.conf files, the cluster needs to be reloaded to pick up the changes.
From the command line: pg_ctl reload
From within a db (as superuser): select pg_reload_conf();
From PGAdmin: right-click db name, select “Reload Configuration”
Note: the reload is not sufficient for changes like enabling archiving, changing shared_buffers, etc — those require a cluster restart.