Micronaut Framework - Connect to AWS secret manager is failed when calling from AWS lambda

Question

I have stored values in AWS secret manager using secret name : config/awsservices/db. I want to fetch these values using Micronaut framework. below the the configuration -

bootstrap.yml

micronaut:
  config-client:
    enabled: true
  application:
    name: awsservices
  
aws:
  secretsmanager:
    secrets:
      - secret-name: /config/awsservices/db

application.yml

username: ${username}

Micronaut code:

public class FunctionRequestHandler extends MicronautRequestHandler<APIGatewayProxyRequestEvent, APIGatewayProxyResponseEvent> {
    
    @Value("${username}")
    public String username;
    
    @Override
    public APIGatewayProxyResponseEvent execute(APIGatewayProxyRequestEvent input) {
        System.out.println("-------------- Inside Main Function -------------");
        APIGatewayProxyResponseEvent response = new APIGatewayProxyResponseEvent();
        try {
            
            System.out.println("-- username : "+username);
            response.setStatusCode(200);
            response.setBody("");
        } catch (IOException e) {
            response.setStatusCode(500);
        }
        return response;
    }
}

In the logs, i am getting username is null.

How to fetch values from secret manager?