1. General Results, most used to calculate the result A name "cheaptextbooks.com" is domain, public suffix is "com", top-level-domain-type is "generic", tld-manager is "VeriSign Global Registry Services" A good: All ip addresses are public addresses A good: No asked Authoritative Name Server had a timeout A good: destination is https A Good: All urls with http status 200/404 have a complete Content-Type header (MediaType / MediaSubType + correct charset) A http://cheaptextbooks.com/ 104.236.3.238 https://cheaptextbooks.com/ correct redirect http - https with the same domain name A http://www.cheaptextbooks.com/ 104.236.3.238 https://www.cheaptextbooks.com/ correct redirect http - https with the same domain name B https://cheaptextbooks.com/ 104.236.3.238 Missing HSTS-Header B https://www.cheaptextbooks.com/ 104.236.3.238 Missing HSTS-Header B https://cheaptextbooks.com/ 104.236.3.238 PHPSESSID=2ch4r9lrejs4nvgoejf1cqamb3; Path=/; Domain=cheaptextbooks.com Cookie sent via https, but not marked as secure B https://www.cheaptextbooks.com/ 104.236.3.238 PHPSESSID=hrut7emij13mqvhea33ttmage0; Path=/; Domain=www.cheaptextbooks.com Cookie sent via https, but not marked as secure C Error - no preferred version www or non-www. Select one version as preferred version, then add a redirect https + not-preferred version to https + preferred version. Perhaps in your port 443 vHost something like "RewriteEngine on" + "RewriteCond %{SERVER_NAME} = example.com" + "ReWriteRule ^ https://www.example.com%{REQUEST_URI} [END,QSA,R=permanent]" (three rows, without the "). That should create a redirect https + example.com ⇒ https + www.example.com. Or switch both values to use the non-www version as your preferred version. C Error - more then one version with Http-Status 200. After all redirects, all users (and search engines) should see the same https url: Non-www or www, but not both with http status 200. 2. DNS- and NameServer - Checks A Good: Nameserver supports TCP connections: 2 good Nameserver A Good: Nameserver supports Echo Capitalization: 2 good Nameserver A Good: Nameserver supports EDNS with max. 512 Byte Udp payload, message is smaller: 2 good Nameserver A Good: Nameserver has passed 10 EDNS-Checks (OP100, FLAGS, V1, V1OP100, V1FLAGS, DNSSEC, V1DNSSEC, NSID, COOKIE, CLIENTSUBNET): 13 good Nameserver Nameserver doesn't pass all EDNS-Checks: ns39.worldnic.com: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok (worldnic). COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns39.worldnic.com / 207.204.40.120: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok (worldnic). COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns40.worldnic.com / 207.204.21.120: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok (worldnic). COOKIE: ok. CLIENTSUBNET: ok. A Good: All SOA have the same Serial Number Warning: No CAA entry with issue/issuewild found, every CAA can create a certificate. Read https://en.wikipedia.org/wiki/DNS_Certification_Authority_Authorization to learn some basics about the idea of CAA. Your name server must support such an entry. Not all dns providers support CAA entries. 3. Content- and Performance-critical Checks A Good: All checks /.well-known/acme-challenge/random-filename without redirects answer with the expected http status 404 - Not Found. Creating a Letsencrypt certificate via http-01 challenge should work. If it doesn't work: Check your vHost configuration (apachectl -S, httpd -S, nginx -T). Every combination of port and ServerName / ServerAlias (Apache) or Server (Nginx) must be unique. Merge duplicated entries in one vHost. If you use an IIS, extensionless files must be allowed in the /.well-known/acme-challenge subdirectory. Create a web.config in that directory. Content: <configuration><system.webServer><staticContent><mimeMap fileExtension="." mimeType="text/plain" /></staticContent></system.webServer></configuration>. If you have a redirect http ⇒ https, that's ok, Letsencrypt follows such redirects to port 80 / 443 (same or other server). There must be a certificate. But the certificate may be expired, self signed or with a not matching domain name. Checking the validation file Letsencrypt ignores such certificate errors. Trouble creating a certificate? Use https://community.letsencrypt.org/ to ask. A Good: Domainname is not on the "Specially Designated Nationals And Blocked Persons List" (SDN). That's an US-list of individuals and companies owned or controlled by, or acting for or on behalf of, targeted countries. It also lists individuals, groups, and entities, such as terrorists and narcotics traffickers designated under programs that are not country-specific. Collectively, such individuals and companies are called "Specially Designated Nationals" or "SDNs." Their assets are blocked and U.S. persons are generally prohibited from dealing with them. So if a domain name is on that list, it's impossible to create a Letsencrypt certificate with that domain name. Check the list manual - https://www.treasury.gov/resource-center/sanctions/sdn-list/pages/default.aspx https://cheaptextbooks.com/.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de 3.787 seconds Warning: 404 needs more then one second https://www.cheaptextbooks.com/.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de 3.990 seconds Warning: 404 needs more then one second A Duration: 82433 milliseconds, 82.433 seconds