I left one there, your tutorial will not work in every case because Let's Encrypt always performs a validation check and will revoke the certificate.
Go and check it if you want, if you really want a Let's Encrypt/SSLForFree Certificate you can use it with CloudFlare by adding a TXT record through Cloudflare DNS.
It will not work if you have CloudFlare from vPanel, if you have CloudFlare from there you can use the Manua Verification, not the DNS one, and it will work.