gollum.at has an A (IPv4) record (80.64.140.85) 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://gollum.at/.well-known/acme-challenge/letsdebug-test": dial tcp 80.64.140.85:80: connect: connection refused
Trace:
@0ms: Making a request to http://gollum.at/.well-known/acme-challenge/letsdebug-test (using initial IP 80.64.140.85)
@0ms: Dialing 80.64.140.85
@102ms: Experienced error: dial tcp 80.64.140.85:80: connect: connection refused