atw.name has an AAAA (IPv6) record (2605:2700:0:3:a800:ff:fe85:7436) but a test request to this address over port 80 did not succeed. Your web server must have at least one working IPv4 or IPv6 address. You should either ensure that validation requests to this domain succeed over IPv6, or remove its AAAA record.
Get http://atw.name/.well-known/acme-challenge/letsdebug-test: dial tcp [2605:2700:0:3:a800:ff:fe85:7436]:80: connect: no route to host
Trace:
@0ms: Making a request to http://atw.name/.well-known/acme-challenge/letsdebug-test (using initial IP 2605:2700:0:3:a800:ff:fe85:7436)
@0ms: Dialing 2605:2700:0:3:a800:ff:fe85:7436
@3183ms: Experienced error: dial tcp [2605:2700:0:3:a800:ff:fe85:7436]:80: connect: no route to host