As of yesterday we are running Moodle 3.7.2+ (Build: 20191012). We have our environment configured to use Badgr as the external backpack connection. We can create and award site and course badges. Users can connect to their own Badgr accounts through profile preferences. The Backpack settings are valid (same issuer email address and password used for the Badgr 'admin' account).
When a user clicks "Add to backpack", moodle returns an "Invalid Request."
What are we doing wrong?