1. General Results, most used to calculate the result A name "165.227.160.134" is ipv4 address, public suffix is not defined A good: All ip addresses are public addresses A good - only one version with Http-Status 200 A Good: No cookie sent via http. A Good: Some urls with http status 200/404 have a complete Content-Type header (MediaType / MediaSubType + correct charset):0 complete Content-Type - header (2 urls) http://165.227.160.134/ 165.227.160.134 Url with incomplete Content-Type - header - missing charset http://165.227.160.134/.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de 165.227.160.134 Url with incomplete Content-Type - header - missing charset H fatal error: No https - result with http-status 200, no encryption H Fatal error: http result with http-status 200, no encryption. Add a redirect http ⇒ https, so every connection is secure. 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. 2. DNS- and NameServer - Checks 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 Info: No img element found, no alt attribute checked A Duration: 6063 milliseconds, 6.063 seconds