When using Advanced Authentication for the Forgotten Password module, you must ensure the following:
Install and configure the Advanced Authentication server version 5.6 Patch Update 1 or later.
For more information about configuring the Advanced Authentication server, see the Advance Authentication Server Administration Guide.
Create and configure the Advanced Authentication repositories. For more information, see Adding a Repository
in the Advance Authentication Server Administration Guide.
A good understand of OAuth2. For more information, see https://oauth.net/2.