1. General Results, most used to calculate the result A name "mail.isitwetyet.com" is subdomain, 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 DNS: "Name Error" means: No www-dns-entry defined. This isn't a problem A Good: destination is https A Good - only one version with Http-Status 200 A Good: one preferred version: non-www is preferred A Good: every cookie sent via https is marked as secure HSTS-Preload-Status: unknown. Domain never included in the Preload-list. Check https://hstspreload.org/ to learn some basics about the Google-Preload-List. A Good: All urls with http status 200/404 have a complete Content-Type header (MediaType / MediaSubType + correct charset) A http://mail.isitwetyet.com/ 157.230.157.127 https://mail.isitwetyet.com/ Correct redirect http - https with the same domain name B https://mail.isitwetyet.com/ 157.230.157.127 Missing HSTS-Header N 157.230.157.127:993 Error - Certificate isn't trusted, RemoteCertificateNameMismatch N 157.230.157.127:995 Error - Certificate isn't trusted, RemoteCertificateNameMismatch 2. Header-Checks (alpha, started 2022-10-23, may be buggy / incomplete) 3. DNS- and NameServer - Checks A Good: Nameserver supports TCP connections: 1 good Nameserver A Good: Nameserver supports Echo Capitalization: 1 good Nameserver A Good: Nameserver supports EDNS with max. 512 Byte Udp payload, message is smaller: 1 good Nameserver A Good: Nameserver has passed 10 EDNS-Checks (OP100, FLAGS, V1, V1OP100, V1FLAGS, DNSSEC, V1DNSSEC, NSID, COOKIE, CLIENTSUBNET): 1 good Nameserver Nameserver doesn't pass all EDNS-Checks: ns1.maido3.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 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. https://mail.isitwetyet.com/ 157.230.157.127 Warning: https result with status 200 and size greater then 1024 Bytes without GZip found. Add GZip support so the html content is compressed. https://mail.isitwetyet.com/ 157.230.157.127 Warning: Https + http status 200 + Inline CSS / JavaScript found. Don't use inline CSS / JavaScript. These are compiled and re-used ressources, save these with a long Cache-Control max-age - header. https://mail.isitwetyet.com/ 157.230.157.127 Warning: Https result with status 200 found, Html-Content is too big. Should be max. 110 %. May contain inline CSS / JavaScript, too much comments or white space. Re-used ressources - create files with a long Cache-Control max-age header. Remove comments and white space. https://mail.isitwetyet.com/ 157.230.157.127 Warning: Https connections (Standard Port 443) found without support of the http/2 protocol via ALPN. Http/2 is the new Http-Version (old: http 1.1) with some important new features. Update your server software so http/2 is available. Only one TCP-connection per Server (that's a performance boost), Header-Compression and Server Pushs are available. Domain Sharding and Inline-CSS/Javascript shouldn't used with http/2. Warning: CSS / JavaScript found without GZip support. Send these ressources with GZip. 8 external CSS / JavaScript files without GZip found - 0 with GZip, 8 complete A Good: All images with internal compression not sent via GZip. Images (.png, .jpg) are already compressed, so an additional GZip isn't helpful. 1 images (type image/png, image/jpg) found without additional GZip. Not required because these images are already compressed Warning: CSS / JavaScript files with a missing or too short Cache-Control header found. Browsers should cache and re-use these files. 8 external CSS / JavaScript files without Cache-Control-Header, 0 with Cache-Control, but no max-age, 0 with Cache-Control max-age too short (minimum 7 days), 0 with Cache-Control long enough, 8 complete. Warning: Images with a missing or too short Cache-Control header found. Browsers should cache and re-use these files. 1 image files without Cache-Control-Header, 0 with Cache-Control, but no max-age, 0 with Cache-Control max-age too short (minimum 7 days), 0 with Cache-Control long enough, 1 complete. 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://mail.isitwetyet.com/.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de 4.370 seconds Warning: 404 needs more then one second A Duration: 77586 milliseconds, 77.586 seconds