Control not passing to Controller Advice class

Question

I am using Spring Webflux (3.2.2) and Spring Graphql(3.2.2) . I have implemented a WebGraphQlInterceptor which looks for a request header. If its not found , I am throwing a Custom Exception . I have defined a Controller Advice class which has a method to handle Custom Exception , but seems like control is not going to that advice method.

@ControllerAdvice
@Slf4j
@Order(Ordered.HIGHEST_PRECEDENCE)
public class GraphQLExceptionHandler {

    

    @GraphQlExceptionHandler(CustomException.class)
    public GraphQLError handleCustomException(CustomException e) {
        return GraphQLError.newError()
                .errorType(resolve(e.errorCode))
                .message(e.getMessage())
                .build();
    }

    
    @GraphQlExceptionHandler(Exception.class)
    @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
    public GraphQLError handleException(Exception e) {
        return GraphQLError.newError()
                .errorType(ErrorType.INTERNAL_ERROR)
                .message(e.getMessage())
                .build();
    }

    @ExceptionHandler(CustomException.class)
    public final Mono<ResponseEntity<Map<String, Object>>> handleCustomExceptions(CustomException ex,
                                                                                 ServerWebExchange exchange) {
        log.info("Application Exception occurred : {} ", ex.getMessage());
        ErrorDetails errorDetails = new ErrorDetails(ex.errorCode, ex.getMessage(), ex,
                exchange.getRequest().getPath().value());
        return Mono.just(ResponseEntity.status(HttpStatus.resolve(ex.errorCode)).body(formatError(errorDetails)));
    }

    /**
     * Handle exceptions.
     *
     * @param ex      the ex
     * @param request the request
     * @return the response entity
     */
    @ResponseStatus(INTERNAL_SERVER_ERROR)
    @ExceptionHandler(Exception.class)
    public final Mono<ResponseEntity<Map<String, Object>>> handleExceptions(Exception ex, ServerWebExchange exchange) {
        log.error("Exception occurred : {0}", ex);
        ErrorDetails errorDetails = new ErrorDetails(INTERNAL_SERVER_ERROR.value(),
                "Something went wrong, please try again after sometime", ex, exchange.getRequest().getPath().value());
        return Mono.just(ResponseEntity.status(INTERNAL_SERVER_ERROR).body(formatError(errorDetails)));
    }

    /**
     * Format error.
     *
     * @param errorDetails the error details
     * @return the map
     */
    private Map<String, Object> formatError(ErrorDetails errorDetails) {
        Map<String, Object> error = new HashMap<>();
        error.put("errors", errorDetails);
        return error;
    }


    private ErrorType resolve(int errorCode) {
        return switch (errorCode) {
            case 401 -> ErrorType.UNAUTHORIZED;
            case 403 -> ErrorType.FORBIDDEN;
            case 404 -> ErrorType.NOT_FOUND;
            default -> ErrorType.INTERNAL_ERROR;
        };
    }
}

My Custom Interceptor

@Component
public class RequestHeaderInterceptor implements WebGraphQlInterceptor {

    public static final String AUTHORIZATION_HEADER_KEY = "Authorization";

    @NotNull
    @Override
    public Mono<WebGraphQlResponse> intercept(WebGraphQlRequest request, Chain chain) {
        String value = request.getHeaders().getFirst(AUTHORIZATION_HEADER_KEY);
        if (value == null) {
            throw new CustomException(ErrorMessage.AUTH_ID_NOT_FOUND);
        }
        request.configureExecutionInput((executionInput, builder) ->
                builder.graphQLContext(Collections.singletonMap("authHeader", value)).build());
        return chain.next(request);
    }
}

What am I missing .