gschmidt.duckdns.org has an A (IPv4) record (84.28.65.36) 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.
A timeout was experienced while communicating with gschmidt.duckdns.org/84.28.65.36: Get "http://gschmidt.duckdns.org/.well-known/acme-challenge/letsdebug-test": context deadline exceeded
Trace:
@0ms: Making a request to http://gschmidt.duckdns.org/.well-known/acme-challenge/letsdebug-test (using initial IP 84.28.65.36)
@0ms: Dialing 84.28.65.36
@10001ms: Experienced error: context deadline exceeded
A test authorization for gschmidt.duckdns.org to the Let's Encrypt staging service has revealed issues that may prevent any certificate for this domain being issued.
84.28.65.36: Fetching http://gschmidt.duckdns.org/.well-known/acme-challenge/MQCRUJtaQSgltfJ1zhLS2tRca7H9De14Xc6c0VkF5Xg: Timeout during connect (likely firewall problem)