1. General Results, most used to calculate the result A name "test.backtablestudios.com" is subdomain, public suffix is ".com", top-level-domain is ".com", top-level-domain-type is "generic", tld-manager is "VeriSign Global Registry Services", num .com-domains preloaded: 85538 (complete: 220007) A Good: All ip addresses are public addresses Warning: Only one ip address found: test.backtablestudios.com has only one ip address. Warning: No ipv6 address found. Ipv6 is the future with a lot of new features. So every domain name should have an ipv6 address. See https://en.wikipedia.org/wiki/IPv6: test.backtablestudios.com has no ipv6 address. A Good: No asked Authoritative Name Server had a timeout A DNS: "Name Error" means: No www-dns-entry defined. This isn't a problem A Good: No cookie sent via http. HSTS-Preload-Status: unknown. Domain never included in the Preload-list. Check https://hstspreload.org/ to learn some basics about the Google-Preload-List. C Error - no version with Http-Status 200 D http://test.backtablestudios.com/ 192.64.119.223 http://danlands.tplinkdns.com Wrong redirect one domain http to other domain http. First redirect to https without changing the domain, so no new dns query is required. So the server can send the HSTS header. That's fundamental using HSTS (Http Strict Transport Security). First step: Add correct redirects http ⇒ https. Perhaps in your port 80 vHost something like "RewriteEngine on" + "RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,QSA,R=permanent]" (two rows, without the "). Don't add this in your port 443 vHost, that would create a loop. Then recheck your domain, should be Grade C. There is the rule to select one https version as preferred version. D http://test.backtablestudios.com/.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de 192.64.119.223 http://danlands.tplinkdns.com Wrong redirect one domain http to other domain http. First redirect to https without changing the domain, so no new dns query is required. So the server can send the HSTS header. That's fundamental using HSTS (Http Strict Transport Security). First step: Add correct redirects http ⇒ https. Perhaps in your port 80 vHost something like "RewriteEngine on" + "RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,QSA,R=permanent]" (two rows, without the "). Don't add this in your port 443 vHost, that would create a loop. Then recheck your domain, should be Grade C. There is the rule to select one https version as preferred version. H Fatal error: No https - result with http-status 200, no encryption R http://test.backtablestudios.com/ 192.64.119.223 http://danlands.tplinkdns.com Redirect to not existing domain R http://test.backtablestudios.com/.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de 192.64.119.223 http://danlands.tplinkdns.com Redirect to not existing domain Info: Checking the ip addresses of that domain name not exact one certificate found. So it's impossible to check if that domain requires Server Name Indication (SNI).: Domain test.backtablestudios.com, 1 ip addresses. B No _mta-sts TXT record found (mta-sts: Mail Transfer Agent Strict Transport Security - see RFC 8461). Read the result of server-daten.de (Url-Checks, Comments, Connections and DomainServiceRecords) to see a complete definition. Domainname: _mta-sts.test.backtablestudios.com 2. Header-Checks (alpha, started 2022-10-23, may be buggy / incomplete) U No https result with http status 2** or 4** (standard-check) found, no header checked. 3. DNS- and NameServer - Checks A Info:: 22 Root-climbing DNS Queries required to find all IPv4- and IPv6-Addresses of 2 Name Servers. A Info:: 22 Queries complete, 22 with IPv6, 0 with IPv4. A Good: All DNS Queries done via IPv6. Bad (greater 8):: An average of 11.0 queries per domain name server required to find all ip addresses of all name servers. A Info:: 2 different Name Servers found: dns1.registrar-servers.com, dns2.registrar-servers.com, 2 Name Servers included in Delegation: dns1.registrar-servers.com, dns2.registrar-servers.com, 2 Name Servers included in 1 Zone definitions: dns1.registrar-servers.com, dns2.registrar-servers.com, 1 Name Servers listed in SOA.Primary: dns1.registrar-servers.com. A Good: Only one SOA.Primary Name Server found.: dns1.registrar-servers.com. A Good: SOA.Primary Name Server included in the delegation set.: dns1.registrar-servers.com. A Good: Consistency between delegation and zone. The set of NS records served by the authoritative name servers must match those proposed for the delegation in the parent zone. Ordered list of name servers: dns1.registrar-servers.com, dns2.registrar-servers.com A Good: All Name Server Domain Names have a Public Suffix. A Good: All Name Server Domain Names ending with a Public Suffix have minimal one IPv4- or IPv6 address. A Good: All Name Server ip addresses are public. A Good: Minimal 2 different name servers (public suffix and public ip address) found: 2 different Name Servers found A Good: All name servers have ipv4- and ipv6-addresses.: 2 different Name Servers found Warning: All Name Servers have the same Top Level Domain / Public Suffix. If there is a problem with that Top Level Domain, your domain may be affected. Better: Use Name Servers with different top level domains.: 2 Name Servers, 1 Top Level Domain: com Warning: All Name Servers have the same domain name. If there is a problem with that domain name (or with the name servers of that domain name), your domain may be affected. Better: Use Name Servers with different domain names / different top level domains.: Only one domain name used: registrar-servers.com Warning: All Name Servers from the same Country / IP location.: 2 Name Servers, 1 Countries: US A Info: Ipv4-Subnet-list: 2 Name Servers, 1 different subnets (first Byte): 156., 1 different subnets (first two Bytes): 156.154., 2 different subnets (first three Bytes): 156.154.132., 156.154.133. A Good: Name Server IPv4-addresses from different subnet found: A Info: IPv6-Subnet-list: 2 Name Servers with IPv6, 1 different subnets (first block): 2610:, 1 different subnets (first two blocks): 2610:00a1:, 2 different subnets (first three blocks): 2610:00a1:1024:, 2610:00a1:1025:, 2 different subnets (first four blocks): 2610:00a1:1024:0000:, 2610:00a1:1025:0000: A Good: Name Server IPv6 addresses from different subnets found. 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): 2 good Nameserver Nameserver doesn't pass all EDNS-Checks: dns1.registrar-servers.com: OP100: no result. FLAGS: no result. V1: no result. V1OP100: no result. V1FLAGS: no result. DNSSEC: no result. V1DNSSEC: no result. NSID: no result. COOKIE: no result. CLIENTSUBNET: no result. 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. 4. Content- and Performance-critical Checks Fatal: All checks of /.well-known/acme-challenge/random-filename have a redirect, destination doesn't have the random filename. Creating a Letsencrypt certificate via http-01 challenge may not work. Trouble creating a certificate? Use https://community.letsencrypt.org/ to ask. A Good: All checked attribute values are enclosed in quotation marks (" or '). A Info: No img element found, no alt attribute checked 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 A Duration: 85377 milliseconds, 85.377 seconds