mod_oauth2 with Mattermost as authorization server

[Bengrunt]

Hello, I'm trying to use a Mattermost instance as a OAuth2.0 Authorization server to protect some static pages served by Apache HTTPd using mod_oauth.

In the relevant Mattermost documentation it is stated that Mattermost only supports some specific authorization flow. Will I be able to configure mod_oauth is this fashion ? Does mod_oauth2 support "Authorization code grant" (RFC 6749?

So far my attempts failed.

Thanks a lot for your help!