Jayadevan M <maymala(dot)jayadevan(at)gmail(dot)com> writes:
> back to md5
> psql -h localhost
> psql: FATAL: password authentication failed for user "postgres"
> [ but there's no .pgpass file ]
Perhaps the postgres user has a password that's marked as expired
in pg_authid.rolvaliduntil? Try
select rolname, rolvaliduntil from pg_authid;
regards, tom lane