> (I might be quite wrong with all the following, it's mostly an observation)

[ghost]

(I might be quite wrong with all the following, it's mostly an observation)
When trying to create a certificate for a host that resolves to an IPv6 address only, the challenge is done via IPv6 as well, for obvious reasons.
acme-nosudo cannot deal with that, "BaseHTTPServer.HTTPServer(('0.0.0.0', 80)" is hard-coded but IPv4 only.
Workaround for me should be: "socat TCP6-LISTEN:80 TCP4:127.0.0.1:80" - not tested since LE doesn't like me now: "urllib2.HTTPError: HTTP Error 503: Service Temporarily Unavailable". Possibly since I've requested a challenge too often.

Originally posted by @patrickfantastic88 in #102 (comment)