Let's try to configure Odoo with "root" access the the PostgreSQL database so it can perform any required action to recover its db.
Using a file editor, edit the properties below in the
db_password = XXXXX
db_user = bn_odoo
with the values below, where
YYYYY is the database password for the "postgres" user (chek this docs):
db_password = YYYYY
db_user = postgres
Then, restart the services running the command below:
sudo /opt/bitnami/ctlscript.sh restart
Finally, try to access to your site again.