Installer failing at cyberpanel website

New Ubuntu 22 install on top ov Proxmox VE 7.4 using IPv6 only for networking.

root@cyber1:~# sh <(curl https://cyberpanel.net/install.sh || wget -O - https://cyberpanel.net/install.sh)

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  2344  100  2344    0     0   4805      0 --:--:-- --:--:-- --:--:--  4803

wget is already the newest version (1.21.2-2ubuntu1).
curl is already the newest version (7.81.0-1ubuntu1.15).
0 upgraded, 0 newly installed, 0 to remove and 5 not upgraded.

chmod: cannot access 'cyberpanel.sh': No such file or directory
/dev/fd/63: 59: ./cyberpanel.sh: not found

ping test:

root@cyber1:~# ping6 google.com
PING google.com(yul03s04-in-x0e.1e100.net (2607:f8b0:4020:806::200e)) 56 data bytes

dig:

root@cyber1:~# dig cyberpanel.net

; <<>> DiG 9.18.18-0ubuntu0.22.04.2-Ubuntu <<>> cyberpanel.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13523
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;cyberpanel.net.                        IN      A

;; ANSWER SECTION:
cyberpanel.net.         300     IN      A       172.67.203.238
cyberpanel.net.         300     IN      A       104.21.44.216

;; Query time: 20 msec
;; SERVER: 2001:4860:4860::8888#53(2001:4860:4860::8888) (UDP)
;; WHEN: Mon Mar 25 15:11:33 UTC 2024
;; MSG SIZE  rcvd: 75

curl attempt:

root@cyber1:~# curl -o cyberpanel.sh 'https://cyberpanel.sh/?dl&Ubuntu'

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0

curl: (7) Couldn't connect to server

edit: further testing notes added

it seems that the domain cyberpanel.sh is not configured to accept an ipv6 connection