Copied the file from /install/community-edition-setup/output/oxauth-config.json to /etc/gluu/conf, then restarted gluu with /sbin/gluu-serverd restart
Confirmed that this file didn't exist before though...so strange that this was needed.
Guys from centroxy say that perhaps it was related to ladp or another piece.
Bottom line, we're back up, so we can close the case.