secondary domain not getting auto renewed

[tanpsingh]

In our env, some clients have a primary domain as client.com, and they also have a secondary domain such as www.client.com, which redirects to the primary domain. Resty auto SSL usually generates a separate certificate for both domains; however, it only renews the certificate for the primary domain, but not the secondary domain.
What could be the issue here? We are not seeing any error, also in the openresty logs.

  lua_package_path "/usr/local/openresty/luajit/share/lua/5.1/?.lua;;";
  lua_shared_dict auto_ssl 100m;
  lua_shared_dict auto_ssl_settings 64k;
  resolver 8.8.8.8 ipv6=off;

  init_by_lua_block {
    auto_ssl = (require "resty.auto-ssl").new()
    auto_ssl:set("allow_domain", function(domain)
      return true
    end)
    auto_ssl:init()
  }

  init_worker_by_lua_block {
    auto_ssl:init_worker()
  }

  server {
    listen 443 ssl default_server;
    ssl_certificate_by_lua_block {
      auto_ssl:ssl_certificate()
    }
    ssl_certificate /etc/letsencrypt/live/mydomain.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/mydomain.com/privkey.pem;

  server {
    listen 80 default_server;
    location /.well-known/acme-challenge/ {
      content_by_lua_block {
        auto_ssl:challenge_server()
      }
    }
    location / {
      return 301 https://$host$request_uri;
    }
  }

  server {
    listen 127.0.0.1:8999;
    client_body_buffer_size 128k;
    client_max_body_size 128k;

    location / {
      content_by_lua_block {
        auto_ssl:hook_server()
      }
    }
  }
}