An example of a query:
nonce=7381be76dc&_wp_http_referer=%2Fwp-json%2Fmoserver%2Fauthorize%3Fclient_id%3DUqocZJZFPVsJhIzSmXhlfLAdtiLkDl%26redirect_uri%3Dhttp%253A%252F%252Fsso.app.local%252Flogin%26response_type%3Dcode%26scope%3Dopenid%26state%3Doidc&authorize-dialog=1&authorize=deny
and the reply:
location: https://wp.app.local/wp-json/moserver/authorize?client_id=UqocZJZFPVsJhIzSmXhlfLAdtiLkDl&redirect_uri=http%3A%2F%2Fsso.app.local%2Flogin&response_type=code&scope=openid&state=oidc&prompt=allow
status: 302
Thanks. I was able to use the plugin by manually creating a .well-known/openid-configuration file.