How can I use client_credentials to access another oauth2 resource from spring cloud gateway

Question

I want to use client credentials flow to access an OAuth protected resource from spring cloud gateway

• There is no authentication needed to hit the gateway end point
• The resource is OAuth2 protected and I have to use client credentials flow
• Based on the matching PATH and HEADERS the request will be redirected to the corresponding service using cloud gateway routes in props file
• I need to get the OAuth token from an Auth service and pass the bearer token in the call to the protected resource

Observations:

• The token end point is not called for a token
• I am getting 403 Forbidden error from the protected resource

I have tried many solutions provided in stackoverflow but I am not able to resolve the issue. What am I missing here?

Configuration file:

spring:
  main.web-application-type: reactive
  security:
    oauth2:
      client:
        registration:
          my-app:
            client-id: client-id
            client-secret: client-secret
            authorization-grant-type: client_credentials
        provider:
          my-app:
            token-uri: https://xxxxxxxx.com/oauth2/token

SecurityConfig:

@EnableWebFluxSecurity
public class SecurityConfig {

  @Bean
  public SecurityWebFilterChain springSecurityFilterChain(ServerHttpSecurity http) {
    return http.oauth2Client().and().build();
  }

  @Bean
  public ReactiveOAuth2AuthorizedClientManager authorizedClientManager(
      ReactiveClientRegistrationRepository clientRegistrationRepository,
      ReactiveOAuth2AuthorizedClientService authorizedClientService) {

    ReactiveOAuth2AuthorizedClientProvider authorizedClientProvider =
        ReactiveOAuth2AuthorizedClientProviderBuilder.builder().clientCredentials().build();

    AuthorizedClientServiceReactiveOAuth2AuthorizedClientManager authorizedClientManager =
        new AuthorizedClientServiceReactiveOAuth2AuthorizedClientManager(
            clientRegistrationRepository, authorizedClientService);
    authorizedClientManager.setAuthorizedClientProvider(authorizedClientProvider);

    return authorizedClientManager;
  }

  @Bean
  public WebClient webClient(ReactiveOAuth2AuthorizedClientManager authorizedClientManager) {
    ServerOAuth2AuthorizedClientExchangeFilterFunction oauth =
        new ServerOAuth2AuthorizedClientExchangeFilterFunction(authorizedClientManager);
    return WebClient.builder().filter(oauth).build();
  }
}

App:

@SpringBootApplication(
exclude = {
  SecurityAutoConfiguration.class
})
public class GatewayApplication {

  public static void main(String[] args) {
    SpringApplication.run(GatewayApplication.class, args);
  }
}

POM:

<dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>ch.qos.logback</groupId>
                    <artifactId>logback-classic</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.8</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter</artifactId>
            <version>3.1.0</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
            <version>3.1.0</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-oauth2-client</artifactId>
        </dependency>

        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-codec-http</artifactId>
            <version>4.1.72.Final</version>
        </dependency>

        <dependency>
            <groupId>net.logstash.logback</groupId>
            <artifactId>logstash-logback-encoder</artifactId>
            <version>7.0.1</version>
        </dependency>

    </dependencies>