owncloud-viz.ddns.net has an A (IPv4) record (220.127.116.11) but a request to this address over port 80 did not succeed. Your web server must have at least one working IPv4 or IPv6 address.
Get "http://owncloud-viz.ddns.net/.well-known/acme-challenge/letsdebug-test": dial tcp 18.104.22.168:80: connect: no route to host
@0ms: Making a request to http://owncloud-viz.ddns.net/.well-known/acme-challenge/letsdebug-test (using initial IP 22.214.171.124)
@0ms: Dialing 126.96.36.199
@3088ms: Experienced error: dial tcp 188.8.131.52:80: connect: no route to host
A test authorization for owncloud-viz.ddns.net to the Let's Encrypt staging service has revealed issues that may prevent any certificate for this domain being issued.
184.108.40.206: Fetching http://owncloud-viz.ddns.net/.well-known/acme-challenge/5HfEcpaFHfWLHacuv3ybDuRX1v4BOFMIj_66hJDFOu4: Error getting validation data