Letsencrypt/acme.sh/standaloneについて、ここに記述してください。

socatが動くようになったので、試す。
　　(requires you to be root/sudoer or have permission to listen on port 80 (TCP))
{{{
# .acme.sh/acme.sh --issue --standalone -d moin.qmail.jp 
[2019 JST] Standalone mode.
[2019 JST] Creating domain key
[2019 JST] The domain key is here: /root/.acme.sh/moin.qmail.jp/moin.qmail.jp.key
[2019 JST] Single domain='moin.qmail.jp'
[2019 JST] Getting domain auth token for each domain
[2019 JST] Getting webroot for domain='moin.qmail.jp'
[2019 JST] Getting new-authz for domain='moin.qmail.jp'
[2019 JST] The new-authz request is ok.
[2019 JST] Verifying:moin.qmail.jp
[2019 JST] Standalone mode server
[2019 JST] Success
[2019 JST] Verify finished, start to sign.
tr: �����ʥХ������Ǥ�
[2019 JST] Cert success.
-----BEGIN CERTIFICATE-----
MIIFUzCCBDugAwIBAgISAygaMDLbETzSKE364P+odFcQMA0GCSqGSIb3DQEBCwUA

-----END CERTIFICATE-----
[2019 JST] Your cert is in  /root/.acme.sh/moin.qmail.jp/moin.qmail.jp.cer 
[2019 JST] Your cert key is in  /root/.acme.sh/moin.qmail.jp/moin.qmail.jp.key 
[2019 JST] The intermediate CA cert is in  /root/.acme.sh/moin.qmail.jp/ca.cer 
[2019 JST] And the full chain certs is there:  /root/.acme.sh/moin.qmail.jp/fullchain.cer 
}}}

https://github.com/Neilpang/acme.sh/wiki/How-to-issue-a-cert