What to configure to enforce Open ID login?

I have a working instance of NC, with several MFA solutions available.

I am now trying to make it work with Authelia. I configured Authelia to provide OpenID authentication and filled in the NC OpenID data.

It seems to not be taken into account at all by NC: when I log in, I go though Authelia’s login page, and then get to the NC login page.

I am ready to debug this on my own (there is information on Internat about that) but one thing I do not understand is why there is nothing in the NC logs indicating that there is an attempt to use OpenID. These are the logs when connecting via Authelia (https://auth.example.eu/ is Authenlia on my domain):

172.18.0.11 - - [14/May/2022:06:29:08 +0000] "GET / HTTP/1.1" 302 1307 "https://auth.example.eu/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.67 Safari/537.36"
172.18.0.11 - - [14/May/2022:06:29:09 +0000] "GET /login HTTP/1.1" 302 993 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.67 Safari/537.36"
172.18.0.11 - - [14/May/2022:06:29:09 +0000] "GET /login HTTP/1.1" 200 6884 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.67 Safari/537.36"

(and then the remaining of the login page)

Is there a specific step I should do in order to actually tell NC to use OpenID as the authentication mechanism?