In order to update your email without entering your Discourse installation, you will have to execute a few queries in your PostgreSQL database.
First of all, you need the database credentials, which you can find at the following location:
Next, load the Bitnami environment before connecting to your server:
Once you have the credentials and you have loaded the environment, connect to your PostgreSQL server:
psql -W -U bn_discourse bitnami_discourse
Now, you will be able to execute the necessary SQL commands to change your administrator e-mail:
UPDATE site_settings set email@example.com' WHERE name='notification_email';
UPDATE site_settings SET firstname.lastname@example.org' WHERE name='contact_email';
UPDATE users SET email@example.com' WHERE id='1';
UPDATE email_tokens SET firstname.lastname@example.org' WHERE user_id='1';
I hope it works!