Odoo 503 Service Unavailable
Specific to Odoo on Debian using Apache ProxyPass
You're going to need to modify your current sites SSL configuration at /etc/apache2/sites-enabled/xxx-default-le-ssl.conf.
You most likely utilized the FQDN of your domain. Instead in your ProxyPass section simply change any references of your site's URL (EX: http:/ketech.org:8069 to http:/localhost:8069). Then simply issue a sudo service apache2 restart and you'll be good to go.