A name "hoangtridung.duckdns.org" is domain, public suffix is "duckdns.org", top-level-domain-type is "generic", tld-manager is "Public Interest Registry (PIR)" A good: All ip addresses are public addresses X Fatal error: Nameserver isn't defined or has timeout X Fatal error: Nameserver doesn't support TCP connection: ns1.duckdns.org: Fatal error - no NameServer IP-Address or connection. Details: One or more errors occurred. - No connection could be made because the target machine actively refused it 54.187.92.222:53 X Fatal error: Nameserver doesn't support TCP connection: ns1.duckdns.org / 54.187.92.222: Fatal error - no NameServer IP-Address or connection. Details: One or more errors occurred. - No connection could be made because the target machine actively refused it 54.187.92.222:53 X Fatal error: Nameserver doesn't support TCP connection: ns2.duckdns.org: Fatal error - no NameServer IP-Address or connection. Details: One or more errors occurred. - No connection could be made because the target machine actively refused it 54.191.117.119:53 X Fatal error: Nameserver doesn't support TCP connection: ns2.duckdns.org / 54.191.117.119: Fatal error - no NameServer IP-Address or connection. Details: One or more errors occurred. - No connection could be made because the target machine actively refused it 54.191.117.119:53 X Fatal error: Nameserver doesn't support TCP connection: ns3.duckdns.org: Fatal error - no NameServer IP-Address or connection. Details: One or more errors occurred. - No connection could be made because the target machine actively refused it 52.26.169.94:53 X Fatal error: Nameserver doesn't support TCP connection: ns3.duckdns.org / 52.26.169.94: Fatal error - no NameServer IP-Address or connection. Details: One or more errors occurred. - No connection could be made because the target machine actively refused it 52.26.169.94:53 A Good: Nameserver supports Echo Capitalization: 3 good Nameserver A Good: Nameserver supports EDNS with max. 512 Byte Udp payload, message is smaller: 3 good Nameserver Nameserver doesn't pass all EDNS-Checks: ns1.duckdns.org: 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. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns1.duckdns.org: 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. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns1.duckdns.org / 54.187.92.222: 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. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns2.duckdns.org: 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. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns2.duckdns.org: 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. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns2.duckdns.org / 54.191.117.119: 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. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns3.duckdns.org: 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. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns3.duckdns.org: 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. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns3.duckdns.org / 52.26.169.94: 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. 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. http://hoangtridung.duckdns.org/.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de 14.248.131.243 -14 Fatal: Check of /.well-known/acme-challenge/random-filename has a timeout. Creating a Letsencrypt certificate via http-01 challenge can't work. You need a running webserver (http) and an open port 80. If it's a home server + ipv4, perhaps a correct port forwarding port 80 extern ⇒ working port intern is required. Port 80 / http can redirect to another domain port 80 or port 443, but not other ports. If it's a home server, perhaps your ISP blocks port 80. Then you may use the dns-01 challenge. Trouble creating a certificate? Use https://community.letsencrypt.org/ to ask. http://www.hoangtridung.duckdns.org/.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de 14.248.131.243 -14 Fatal: Check of /.well-known/acme-challenge/random-filename has a timeout. Creating a Letsencrypt certificate via http-01 challenge can't work. You need a running webserver (http) and an open port 80. If it's a home server + ipv4, perhaps a correct port forwarding port 80 extern ⇒ working port intern is required. Port 80 / http can redirect to another domain port 80 or port 443, but not other ports. If it's a home server, perhaps your ISP blocks port 80. Then you may use the dns-01 challenge. 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 A Duration: 204997 milliseconds, 204.997 seconds