...
The following steps are required to configure single application access:
1. Create and enable ClientCredentialsMethod authentication method as described in OAuth 2.0 Client Credentials Grant authentication method - SSO
Add this ClientCredentialsMethod method to site Example.
Allow the ClientCredentialsMethod method for application Client1
Allow the ClientCredentialsMethod method for group Group1.
Allow Group1 to access application Client1.
Now it should be is possible to get the token with Client1 application credentials:
...