Golang ACMEv2 HTTP01 挑战不挑战服务器

对于this code，我正在try 手动HTTP-01挑战，以更好地了解该过程是如何工作的.所有的请求都会返回201/200个响应和预期的机构，我能够成功创建挑战.

然而，ACME服务器似乎从未挑战HTTP服务器.

2022/07/17 13:49:28 challenge response {
  "type": "http-01",
  "status": "pending",
  "url": "https://acme-staging-v02.api.letsencrypt.org/acme/chall-v3/3039193714/PVI-4A",
  "token": "yoevDKY_bARdM5uHmVsk3s5lPK8BsBWC-SfmRN8MkLM"
}

但是，在轮询授权状态时，我可以看到它处于挂起状态:

2022/07/17 13:49:43 authorization response {
  "identifier": {
    "type": "dns",
    "value": "billabull.com"
  },
  "status": "pending",
  "expires": "2022-07-24T13:49:27Z",
  "challenges": [
    {
      "type": "http-01",
      "status": "pending",
      "url": "https://acme-staging-v02.api.letsencrypt.org/acme/chall-v3/3039193714/PVI-4A",
      "token": "yoevDKY_bARdM5uHmVsk3s5lPK8BsBWC-SfmRN8MkLM"
    },
    {
      "type": "dns-01",
      "status": "pending",
      "url": "https://acme-staging-v02.api.letsencrypt.org/acme/chall-v3/3039193714/uHeVHQ",
      "token": "yoevDKY_bARdM5uHmVsk3s5lPK8BsBWC-SfmRN8MkLM"
    },
    {
      "type": "tls-alpn-01",
      "status": "pending",
      "url": "https://acme-staging-v02.api.letsencrypt.org/acme/chall-v3/3039193714/RomB0g",
      "token": "yoevDKY_bARdM5uHmVsk3s5lPK8BsBWC-SfmRN8MkLM"
    }
  ]
}

目前，我在超时之前投票了2分钟(服务器可用)，所以我觉得应该在该时间范围内进行投票.

我还测试了HTTP服务器在域billabull.com的端口80上可用，并且向质询路径发出GET请求确实会返回正确的密钥授权.但是，ACME服务器从未向服务器发出请求.

有人知道为什么ACME服务器可能不会挑战我的服务器吗？