你好，我觉得自己很蠢，因为这看起来应该很明显，但我无法在运行 Ubuntu 18.04 AMI 的 AWS t2.medium 实例上完成 Docker 入门安装。
运行 ./discourse-setup 时，我不断遇到以下错误：
Status: Downloaded newer image for discourse/base:2.0.20200220-2221
app was not started !
./discourse-doctor may help diagnose the problem.
Found 4GB of memory and 2 physical CPU cores
setting db_shared_buffers = 1024MB
setting UNICORN_WORKERS = 4
containers/app.yml memory parameters updated.
Hostname for your Discourse? [discourse.example.com]: discuss.postera.ai
Checking your domain name . . .
WARNING:: This server does not appear to be accessible at discuss.postera.ai:443.
A connection to http://discuss.postera.ai (port 80) also fails.
This suggests that discuss.postera.ai resolves to the wrong IP address
or that traffic is not being routed to your server.
Google: "open ports YOUR CLOUD SERVICE" for information for resolving this problem.
我不确定问题是出在 app was not started，还是因为服务器无法访问。
我已经开放了端口 80 和 443 以允许所有流量，并添加了指向公共 IPv4 地址的 A 记录。在我的本地机器上运行 dig 和 host 命令似乎表明 DNS 映射是正确的。
该实例位于 VPC 的公共子网中。我没有使用负载均衡器（之前试过但无法成功，以为是 nginx 的问题……）。
感谢您的帮助。
