1. 确保在AppSync中配置好subscribe事件的监听器。

2. 确保在node.js中正确地使用AWS SDK for JavaScript。

3. 确保AppSync中的GraphQL模式与node.js中的代码匹配。

4. 确保订阅事件函数中正确地使用GraphQL实时对象（realtime object），如下代码所示：

const AWS = require('aws-sdk');
AWS.config.update({region: process.env.REGION});
const appsync = new AWS.AppSync();
const gql = require('graphql-tag');

const subscription = appsync.subscribe({
  query: gql`subscription onNewComment($postId: ID!) {
    Comment(postId: $postId) {
      id
      content
    }
  }`,
  variables: {postId: '1'},
});

subscription.subscribe({
  next(data) {
    console.log('New comment: ', data);
  },
  error(error) {
    console.log('Error: ', error);
  },
  complete() {
    console.log('Subscription complete');
  },
});

5. 检查订阅事件函数中用于连接实时服务的参数是否正确，如下代码所示：

const WebSocket = require('ws');

const ws = new WebSocket('wss://your-api-id.appsync-realtime-api.your-region.amazonaws.com/graphql', {
  headers: {
    'Sec-WebSocket-Protocol': 'graphql-ws',
    'x-api-key': 'your-api-key',
    Authorization: 'Bearer ' + 'your-jwt-token',
  },
});

ws.on('open', function() {
  console.log('WebSocket connection established');
});

ws.on('message', function(data) {
  console.log('WebSocket message received: ', data);
});

ws.on('close', function() {
  console.log('WebSocket connection closed');
});

以上提到的解决方法应该能够解决在node.js中使用GraphQL订阅事件时出现的问题。