I have an issue with postgres: even though I performed these two commands, below, I still get an error

sqlalchemy.exc.OperationalError: (psycopg2.OperationalError) connection to server at "localhost" (127.0.0.1), port 5433 failed: FATAL: password authentication failed for user "postgres"

Command run netstat -lecat appears:

tcp 0 0 0.0.0.0:5433 0.0.0.0:* LISTEN root 61904.

Command run systemctl status postgresql is Active.

apt install postgresql-contrib

sudo -u postgres psql -c "ALTER USER postgres PASSWORD 'postgres';"

Can you recommend other approaches to investigate?

Thanks.