saul.fi has an A (IPv4) record (212.86.29.159) 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 https://www.saul.fi/.well-known/acme-challenge/letsdebug-test: DNS response for www.saul.fi/AAAA did not have an acceptable response code: SERVFAIL
Trace:
@0ms: Making a request to http://saul.fi/.well-known/acme-challenge/letsdebug-test (using initial IP 212.86.29.159)
@0ms: Dialing 212.86.29.159
@221ms: Server response: HTTP 301 Moved Permanently
@221ms: Received redirect to https://saul.fi/.well-known/acme-challenge/letsdebug-test
@221ms: Dialing 212.86.29.159
@702ms: Server response: HTTP 301 Moved Permanently
@702ms: Received redirect to https://www.saul.fi/.well-known/acme-challenge/letsdebug-test
@1114ms: Experienced error: DNS response for www.saul.fi/AAAA did not have an acceptable response code: SERVFAIL