已经关注公众号，代码如下：

走失败回调，返回errMsg: "requestSubscribeMessage:fail No template data return, verify the template id exist", errCode: 20001

wx.requestSubscribeMessage({
      tmplIds: ['V9xs9Wn20Z4gZwGS0vBlGt0EMwjejLtq00fD2E'],
      success (res) {
        console.log('989',res)
      },
      fail(err){
        console.log('858',err)
      }
    })