You have a non-functioning IPv6 address from an private address space in yor DNS.
$ dig +short cloud.aiskon.net aaaa
fe80::7229:c312:f1c4:dc6a
$ curl -6 https://cloud.aiskon.net
curl: (7) Failed to connect to cloud.aiskon.net port 443 after 2 ms: Couldn't connect to server