无法从Spring Boot向FCM和远程用户发送推送通知？

<dependency>
    <groupId>com.google.firebase</groupId>
    <artifactId>firebase-admin</artifactId>
    <version>7.0.0</version>
</dependency>

@Configuration
public class FcmConfig {

    @Value("${fcm.serverKey}")
    private String serverKey;

    @Bean
    public FirebaseApp firebaseApp() throws IOException {
        FileInputStream serviceAccount = new FileInputStream("path/to/serviceAccountKey.json");

        FirebaseOptions options = new FirebaseOptions.Builder()
                .setCredentials(GoogleCredentials.fromStream(serviceAccount))
                .build();

        return FirebaseApp.initializeApp(options);
    }

    @Bean
    public FirebaseMessaging firebaseMessaging(FirebaseApp firebaseApp) {
        return FirebaseMessaging.getInstance(firebaseApp);
    }
}

@Service
public class PushNotificationService {

    @Autowired
    private FirebaseMessaging firebaseMessaging;

    public void sendPushNotification(String deviceId, String title, String message) {
        Message fcmMessage = Message.builder()
                .setToken(deviceId)
                .setNotification(new Notification(title, message))
                .build();

        try {
            String response = firebaseMessaging.send(fcmMessage);
            System.out.println("Successfully sent message: " + response);
        } catch (FirebaseMessagingException e) {
            System.out.println("Failed to send message: " + e.getMessage());
        }
    }
}