A test authorization for mrrobotcloud.duckdns.org to the Let's Encrypt staging service has revealed issues that may prevent any certificate for this domain being issued.
Connection refused
Challenge update failures for mrrobotcloud.duckdns.org in order https://acme-staging-v02.api.letsencrypt.org/acme/order/5751349/20305514
acme: error code 400 "urn:ietf:params:acme:error:connection": Connection refused
The IANA public suffix is the TLD of the Registered Domain
The TLD for mrrobotcloud.duckdns.org is: org
1 Certificates contributing to rate limits for this domain
Serial: 417319055578290286944709400725202947188573
NotBefore: 2019-01-16 19:40:10 +0000 UTC
Names: [ffmpeg.mrrobotcloud.duckdns.org]
The current status.io status for Let's Encrypt
Operational