Unable to use swagger generated with feign clients with authentication, invalid property

I have trouble using swagger generated feign clients correctly. My service uses the password flow to generate tokens for the clients, the swagger generated feign client along with its configuration is as follows:

feign client configuration:

@Configuration
@EnableConfigurationProperties
public class ClientConfiguration {
public ClientConfiguration() {
}

@Bean
@ConditionalOnProperty({"app.security.oAuth2.client-id"})
public OAuth2FeignRequestInterceptor oAuth2RequestInterceptor() {
    return new OAuth2FeignRequestInterceptor(new DefaultOAuth2ClientContext(), this.oAuth2ResourceDetails());
}

@Bean
@ConditionalOnProperty({"app.security.oAuth2.client-id"})
@ConfigurationProperties("app.security.oAuth2")
public ResourceOwnerPasswordResourceDetails oAuth2ResourceDetails() {
    ResourceOwnerPasswordResourceDetails details = new ResourceOwnerPasswordResourceDetails();
    details.setAccessTokenUri("https://localhost:8000/as/token.oauth2");
    return details;
}
}

feign client definition:

@FeignClient(name = "${app.name:app}", url = "${app.url:https://localhost}", configuration = {ClientConfiguration.class}
)
public interface FlowApiClient extends FlowApi {
}

my application.yml

app:
  name: appName
  url: http://localhost:8080
  security:
    oAuth2:
      client-id: 123
      client-secret: 456
      username: test
      password: test

Then I got following error messages:

Caused by: org.springframework.boot.context.properties.source.InvalidConfigurationPropertyNameException: Configuration property name 'app.security.oAuth2' is not valid