当验证域名时提示403 Forbidden，并且提示：

To fix these errors, please make sure that your domain name was
entered correctly and the DNS A record(s) for that domain
contain(s) the right IP address.

因为默认LNMP 1.3的虚拟主机里是禁止.开头的隐藏文件及目录的。需要将
location ~ /\.
{
deny all;
}
这段配置删掉或注释掉或在这段配置前面加上

location ~ /.well-known {
    allowall;
}

保存，重启nginx。